Annotation of html5/spec/the-iframe-element.html, revision 1.13

1.1       mike        1: <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
                      2: <!DOCTYPE html>
                      3: <!-- when publishing, change bits marked ZZZ --><html lang="en-US-x-Hixie" class="split chapter"><head><title>4.8.2 The iframe element &#8212; HTML5 </title><style type="text/css">
                      4:    pre { margin-left: 2em; white-space: pre-wrap; }
                      5:    h2 { margin: 3em 0 1em 0; }
                      6:    h3 { margin: 2.5em 0 1em 0; }
                      7:    h4 { margin: 2.5em 0 0.75em 0; }
                      8:    h5, h6 { margin: 2.5em 0 1em; }
                      9:    h1 + h2, h1 + h2 + h2 { margin: 0.75em 0 0.75em; }
                     10:    h2 + h3, h3 + h4, h4 + h5, h5 + h6 { margin-top: 0.5em; }
                     11:    p { margin: 1em 0; }
                     12:    hr:not(.top) { display: block; background: none; border: none; padding: 0; margin: 2em 0; height: auto; }
                     13:    dl, dd { margin-top: 0; margin-bottom: 0; }
                     14:    dt { margin-top: 0.75em; margin-bottom: 0.25em; clear: left; }
                     15:    dt + dt { margin-top: 0; }
                     16:    dd dt { margin-top: 0.25em; margin-bottom: 0; }
                     17:    dd p { margin-top: 0; }
                     18:    dd dl + p { margin-top: 1em; }
                     19:    dd table + p { margin-top: 1em; }
                     20:    p + * > li, dd li { margin: 1em 0; }
                     21:    dt, dfn { font-weight: bold; font-style: normal; }
                     22:    dt dfn { font-style: italic; }
                     23:    pre, code { font-size: inherit; font-family: monospace; font-variant: normal; }
                     24:    pre strong { color: black; font: inherit; font-weight: bold; background: yellow; }
                     25:    pre em { font-weight: bolder; font-style: normal; }
                     26:    @media screen { code { color: orangered; } code :link, code :visited { color: inherit; } }
                     27:    var sub { vertical-align: bottom; font-size: smaller; position: relative; top: 0.1em; }
                     28:    table { border-collapse: collapse; border-style: hidden hidden none hidden; }
                     29:    table thead, table tbody { border-bottom: solid; }
                     30:    table tbody th:first-child { border-left: solid; }
                     31:    table tbody th { text-align: left; }
                     32:    table td, table th { border-left: solid; border-right: solid; border-bottom: solid thin; vertical-align: top; padding: 0.2em; }
                     33:    blockquote { margin: 0 0 0 2em; border: 0; padding: 0; font-style: italic; }
                     34: 
                     35:    .bad, .bad *:not(.XXX) { color: gray; border-color: gray; background: transparent; }
                     36:    .matrix, .matrix td { border: none; text-align: right; }
                     37:    .matrix { margin-left: 2em; }
                     38:    .dice-example { border-collapse: collapse; border-style: hidden solid solid hidden; border-width: thin; margin-left: 3em; }
                     39:    .dice-example caption { width: 30em; font-size: smaller; font-style: italic; padding: 0.75em 0; text-align: left; }
                     40:    .dice-example td, .dice-example th { border: solid thin; width: 1.35em; height: 1.05em; text-align: center; padding: 0; }
                     41: 
                     42:    .toc dfn, h1 dfn, h2 dfn, h3 dfn, h4 dfn, h5 dfn, h6 dfn { font: inherit; }
                     43:    img.extra { float: right; }
                     44:    pre.idl { border: solid thin; background: #EEEEEE; color: black; padding: 0.5em 1em; }
                     45:    pre.idl :link, pre.idl :visited { color: inherit; background: transparent; }
                     46:    pre.css { border: solid thin; background: #FFFFEE; color: black; padding: 0.5em 1em; }
                     47:    pre.css:first-line { color: #AAAA50; }
                     48:    dl.domintro { color: green; margin: 2em 0 2em 2em; padding: 0.5em 1em; border: none; background: #DDFFDD; }
                     49:    hr + dl.domintro, div.impl + dl.domintro { margin-top: 2.5em; margin-bottom: 1.5em; }
                     50:    dl.domintro dt, dl.domintro dt * { color: black; text-decoration: none; }
                     51:    dl.domintro dd { margin: 0.5em 0 1em 2em; padding: 0; }
                     52:    dl.domintro dd p { margin: 0.5em 0; }
                     53:    dl.switch { padding-left: 2em; }
                     54:    dl.switch > dt { text-indent: -1.5em; }
                     55:    dl.switch > dt:before { content: '\21AA'; padding: 0 0.5em 0 0; display: inline-block; width: 1em; text-align: right; line-height: 0.5em; }
                     56:    dl.triple { padding: 0 0 0 1em; }
                     57:    dl.triple dt, dl.triple dd { margin: 0; display: inline }
                     58:    dl.triple dt:after { content: ':'; }
                     59:    dl.triple dd:after { content: '\A'; white-space: pre; }
                     60:    .diff-old { text-decoration: line-through; color: silver; background: transparent; }
                     61:    .diff-chg, .diff-new { text-decoration: underline; color: green; background: transparent; }
                     62:    a .diff-new { border-bottom: 1px blue solid; }
                     63: 
                     64:    h2 { page-break-before: always; }
                     65:    h1, h2, h3, h4, h5, h6 { page-break-after: avoid; }
                     66:    h1 + h2, hr + h2.no-toc { page-break-before: auto; }
                     67: 
                     68:    p > span:not([title=""]):not([class="XXX"]):not([class="impl"]), li > span:not([title=""]):not([class="XXX"]):not([class="impl"]) { border-bottom: solid #9999CC; }
                     69: 
                     70:    div.head { margin: 0 0 1em; padding: 1em 0 0 0; }
                     71:    div.head p { margin: 0; }
                     72:    div.head h1 { margin: 0; }
                     73:    div.head .logo { float: right; margin: 0 1em; }
                     74:    div.head .logo img { border: none } /* remove border from top image */
                     75:    div.head dl { margin: 1em 0; }
                     76:    div.head p.copyright, div.head p.alt { font-size: x-small; font-style: oblique; margin: 0; }
                     77: 
                     78:    body > .toc > li { margin-top: 1em; margin-bottom: 1em; }
                     79:    body > .toc.brief > li { margin-top: 0.35em; margin-bottom: 0.35em; }
                     80:    body > .toc > li > * { margin-bottom: 0.5em; }
                     81:    body > .toc > li > * > li > * { margin-bottom: 0.25em; }
                     82:    .toc, .toc li { list-style: none; }
                     83: 
                     84:    .brief { margin-top: 1em; margin-bottom: 1em; line-height: 1.1; }
                     85:    .brief li { margin: 0; padding: 0; }
                     86:    .brief li p { margin: 0; padding: 0; }
                     87: 
                     88:    .category-list { margin-top: -0.75em; margin-bottom: 1em; line-height: 1.5; }
                     89:    .category-list::before { content: '\21D2\A0'; font-size: 1.2em; font-weight: 900; }
                     90:    .category-list li { display: inline; }
                     91:    .category-list li:not(:last-child)::after { content: ', '; }
                     92:    .category-list li > span, .category-list li > a { text-transform: lowercase; }
                     93:    .category-list li * { text-transform: none; } /* don't affect <code> nested in <a> */
                     94: 
                     95:    .XXX { color: #E50000; background: white; border: solid red; padding: 0.5em; margin: 1em 0; }
                     96:    .XXX > :first-child { margin-top: 0; }
                     97:    p .XXX { line-height: 3em; }
                     98:    .annotation { border: solid thin black; background: #0C479D; color: white; position: relative; margin: 8px 0 20px 0; }
                     99:    .annotation:before { position: absolute; left: 0; top: 0; width: 100%; height: 100%; margin: 6px -6px -6px 6px; background: #333333; z-index: -1; content: ''; }
                    100:    .annotation :link, .annotation :visited { color: inherit; }
                    101:    .annotation :link:hover, .annotation :visited:hover { background: transparent; }
                    102:    .annotation span { border: none ! important; }
                    103:    .note { color: green; background: transparent; font-family: sans-serif; }
                    104:    .warning { color: red; background: transparent; }
                    105:    .note, .warning { font-weight: bolder; font-style: italic; }
                    106:    p.note, div.note { padding: 0.5em 2em; }
                    107:    span.note { padding: 0 2em; }
                    108:    .note p:first-child, .warning p:first-child { margin-top: 0; }
                    109:    .note p:last-child, .warning p:last-child { margin-bottom: 0; }
                    110:    .warning:before { font-style: normal; }
                    111:    p.note:before { content: 'Note: '; }
                    112:    p.warning:before { content: '\26A0 Warning! '; }
                    113: 
                    114:    .bookkeeping:before { display: block; content: 'Bookkeeping details'; font-weight: bolder; font-style: italic; }
                    115:    .bookkeeping { font-size: 0.8em; margin: 2em 0; }
                    116:    .bookkeeping p { margin: 0.5em 2em; display: list-item; list-style: square; }
1.12      mike      117:    .bookkeeping dt { margin: 0.5em 2em 0; }
                    118:    .bookkeeping dd { margin: 0 3em 0.5em; }
1.1       mike      119: 
                    120:    h4 { position: relative; z-index: 3; }
                    121:    h4 + .element, h4 + div + .element { margin-top: -2.5em; padding-top: 2em; }
                    122:    .element {
                    123:      background: #EEEEFF;
                    124:      color: black;
                    125:      margin: 0 0 1em 0.15em;
                    126:      padding: 0 1em 0.25em 0.75em;
                    127:      border-left: solid #9999FF 0.25em;
                    128:      position: relative;
                    129:      z-index: 1;
                    130:    }
                    131:    .element:before {
                    132:      position: absolute;
                    133:      z-index: 2;
                    134:      top: 0;
                    135:      left: -1.15em;
                    136:      height: 2em;
                    137:      width: 0.9em;
                    138:      background: #EEEEFF;
                    139:      content: ' ';
                    140:      border-style: none none solid solid;
                    141:      border-color: #9999FF;
                    142:      border-width: 0.25em;
                    143:    }
                    144: 
                    145:    .example { display: block; color: #222222; background: #FCFCFC; border-left: double; margin-left: 2em; padding-left: 1em; }
                    146:    td > .example:only-child { margin: 0 0 0 0.1em; }
                    147: 
                    148:    ul.domTree, ul.domTree ul { padding: 0 0 0 1em; margin: 0; }
                    149:    ul.domTree li { padding: 0; margin: 0; list-style: none; position: relative; }
                    150:    ul.domTree li li { list-style: none; }
                    151:    ul.domTree li:first-child::before { position: absolute; top: 0; height: 0.6em; left: -0.75em; width: 0.5em; border-style: none none solid solid; content: ''; border-width: 0.1em; }
                    152:    ul.domTree li:not(:last-child)::after { position: absolute; top: 0; bottom: -0.6em; left: -0.75em; width: 0.5em; border-style: none none solid solid; content: ''; border-width: 0.1em; }
                    153:    ul.domTree span { font-style: italic; font-family: serif; }
                    154:    ul.domTree .t1 code { color: purple; font-weight: bold; }
                    155:    ul.domTree .t2 { font-style: normal; font-family: monospace; }
                    156:    ul.domTree .t2 .name { color: black; font-weight: bold; }
                    157:    ul.domTree .t2 .value { color: blue; font-weight: normal; }
                    158:    ul.domTree .t3 code, .domTree .t4 code, .domTree .t5 code { color: gray; }
                    159:    ul.domTree .t7 code, .domTree .t8 code { color: green; }
                    160:    ul.domTree .t10 code { color: teal; }
                    161: 
                    162:    body.dfnEnabled dfn { cursor: pointer; }
                    163:    .dfnPanel {
                    164:      display: inline;
                    165:      position: absolute;
                    166:      z-index: 10;
                    167:      height: auto;
                    168:      width: auto;
                    169:      padding: 0.5em 0.75em;
                    170:      font: small sans-serif, Droid Sans Fallback;
                    171:      background: #DDDDDD;
                    172:      color: black;
                    173:      border: outset 0.2em;
                    174:    }
                    175:    .dfnPanel * { margin: 0; padding: 0; font: inherit; text-indent: 0; }
                    176:    .dfnPanel :link, .dfnPanel :visited { color: black; }
                    177:    .dfnPanel p { font-weight: bolder; }
                    178:    .dfnPanel * + p { margin-top: 0.25em; }
                    179:    .dfnPanel li { list-style-position: inside; }
                    180: 
                    181:    #configUI { position: absolute; z-index: 20; top: 10em; right: 1em; width: 11em; font-size: small; }
                    182:    #configUI p { margin: 0.5em 0; padding: 0.3em; background: #EEEEEE; color: black; border: inset thin; }
                    183:    #configUI p label { display: block; }
                    184:    #configUI #updateUI, #configUI .loginUI { text-align: center; }
                    185:    #configUI input[type=button] { display: block; margin: auto; }
1.11      mike      186: 
1.1       mike      187:   </style><style type="text/css">
                    188: 
                    189:    .applies thead th > * { display: block; }
                    190:    .applies thead code { display: block; }
                    191:    .applies tbody th { whitespace: nowrap; }
                    192:    .applies td { text-align: center; }
                    193:    .applies .yes { background: yellow; }
                    194: 
                    195:    .matrix, .matrix td { border: none; text-align: right; }
                    196:    .matrix { margin-left: 2em; }
                    197: 
                    198:    .dice-example { border-collapse: collapse; border-style: hidden solid solid hidden; border-width: thin; margin-left: 3em; }
                    199:    .dice-example caption { width: 30em; font-size: smaller; font-style: italic; padding: 0.75em 0; text-align: left; }
                    200:    .dice-example td, .dice-example th { border: solid thin; width: 1.35em; height: 1.05em; text-align: center; padding: 0; }
                    201: 
                    202:    #table-example-1 { border: solid thin; border-collapse: collapse; margin-left: 3em; }
                    203:    #table-example-1 * { font-family: "Essays1743", serif; line-height: 1.01em; }
                    204:    #table-example-1 caption { padding-bottom: 0.5em; }
                    205:    #table-example-1 thead, #table-example-1 tbody { border: none; }
                    206:    #table-example-1 th, #table-example-1 td { border: solid thin; }
                    207:    #table-example-1 th { font-weight: normal; }
                    208:    #table-example-1 td { border-style: none solid; vertical-align: top; }
                    209:    #table-example-1 th { padding: 0.5em; vertical-align: middle; text-align: center; }
                    210:    #table-example-1 tbody tr:first-child td { padding-top: 0.5em; }
                    211:    #table-example-1 tbody tr:last-child td { padding-bottom: 1.5em; }
                    212:    #table-example-1 tbody td:first-child { padding-left: 2.5em; padding-right: 0; width: 9em; }
                    213:    #table-example-1 tbody td:first-child::after { content: leader(". "); }
                    214:    #table-example-1 tbody td { padding-left: 2em; padding-right: 2em; }
                    215:    #table-example-1 tbody td:first-child + td { width: 10em; }
                    216:    #table-example-1 tbody td:first-child + td ~ td { width: 2.5em; }
                    217:    #table-example-1 tbody td:first-child + td + td + td ~ td { width: 1.25em; }
                    218: 
                    219:    .apple-table-examples { border: none; border-collapse: separate; border-spacing: 1.5em 0em; width: 40em; margin-left: 3em; }
                    220:    .apple-table-examples * { font-family: "Times", serif; }
                    221:    .apple-table-examples td, .apple-table-examples th { border: none; white-space: nowrap; padding-top: 0; padding-bottom: 0; }
                    222:    .apple-table-examples tbody th:first-child { border-left: none; width: 100%; }
                    223:    .apple-table-examples thead th:first-child ~ th { font-size: smaller; font-weight: bolder; border-bottom: solid 2px; text-align: center; }
                    224:    .apple-table-examples tbody th::after, .apple-table-examples tfoot th::after { content: leader(". ") }
                    225:    .apple-table-examples tbody th, .apple-table-examples tfoot th { font: inherit; text-align: left; }
                    226:    .apple-table-examples td { text-align: right; vertical-align: top; }
                    227:    .apple-table-examples.e1 tbody tr:last-child td { border-bottom: solid 1px; }
                    228:    .apple-table-examples.e1 tbody + tbody tr:last-child td { border-bottom: double 3px; }
                    229:    .apple-table-examples.e2 th[scope=row] { padding-left: 1em; }
                    230:    .apple-table-examples sup { line-height: 0; }
                    231: 
                    232:    .details-example img { vertical-align: top; }
                    233: 
                    234:    #named-character-references-table {
                    235:      font-size: 0.6em;
                    236:      column-width: 28em;
                    237:      column-gap: 1em;
                    238:      -moz-column-width: 28em;
                    239:      -moz-column-gap: 1em;
                    240:      -webkit-column-width: 28em;
                    241:      -webkit-column-gap: 1em;
                    242:    }
                    243:    #named-character-references-table > table > tbody > tr > td:last-child { text-align: center; }
                    244:    #named-character-references-table > table > tbody > tr > td:last-child:hover > span { position: absolute; top: auto; left: auto; margin-left: 0.5em; line-height: 1.2; font-size: 5em; border: outset; padding: 0.25em 0.5em; background: white; width: 1.25em; height: auto; text-align: center; }
                    245: 
1.2       mike      246:    .glyph.control { color: red; }
                    247: 
1.4       mike      248:    @font-face {
                    249:      font-family: 'Essays1743';
                    250:      src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743.ttf');
                    251:    }
                    252:    @font-face {
                    253:      font-family: 'Essays1743';
                    254:      font-weight: bold;
                    255:      src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-Bold.ttf');
                    256:    }
                    257:    @font-face {
                    258:      font-family: 'Essays1743';
                    259:      font-style: italic;
                    260:      src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-Italic.ttf');
                    261:    }
                    262:    @font-face {
                    263:      font-family: 'Essays1743';
                    264:      font-style: italic;
                    265:      font-weight: bold;
                    266:      src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-BoldItalic.ttf');
                    267:    }
                    268: 
1.1       mike      269:   </style><style type="text/css">
                    270:    .domintro:before { display: table; margin: -1em -0.5em -0.5em auto; width: auto; content: 'This box is non-normative. Implementation requirements are given below this box.'; color: black; font-style: italic; border: solid 2px; background: white; padding: 0 0.25em; }
                    271:   </style><link href="data:text/css," id="complete" rel="stylesheet" title="Complete specification"><link href="data:text/css,.impl%20%7B%20display:%20none;%20%7D%0Ahtml%20%7B%20border:%20solid%20yellow;%20%7D%20.domintro:before%20%7B%20display:%20none;%20%7D" id="author" rel="alternate stylesheet" title="Author documentation only"><link href="data:text/css,.impl%20%7B%20background:%20%23FFEEEE;%20%7D%20.domintro:before%20%7B%20background:%20%23FFEEEE;%20%7D" id="highlight" rel="alternate stylesheet" title="Highlight implementation requirements"><script type="text/javascript">
                    272:    function getCookie(name) {
                    273:      var params = location.search.substr(1).split("&");
                    274:      for (var index = 0; index < params.length; index++) {
                    275:        if (params[index] == name)
                    276:          return "1";
                    277:        var data = params[index].split("=");
                    278:        if (data[0] == name)
                    279:          return unescape(data[1]);
                    280:      }
                    281:      var cookies = document.cookie.split("; ");
                    282:      for (var index = 0; index < cookies.length; index++) {
                    283:        var data = cookies[index].split("=");
                    284:        if (data[0] == name)
                    285:          return unescape(data[1]);
                    286:      }
                    287:      return null;
                    288:    }
                    289:    function load(script) {
                    290:      var e = document.createElement('script');
                    291:      e.setAttribute('src', 'http://www.whatwg.org/specs/web-apps/current-work/' + script + '?' + encodeURIComponent(location) + '&' + encodeURIComponent(document.referrer));
                    292:      document.body.appendChild(e);
                    293:    }
                    294:    function init() {
                    295:      if (location.search == '?slow-browser')
                    296:        return;
                    297:      var configUI = document.createElement('div');
                    298:      configUI.id = 'configUI';
                    299:      document.body.appendChild(configUI);
                    300:      // load('reviewer.js'); // would need cross-site XHR
                    301:      if (document.getElementById('head'))
                    302:        load('toc.js');
                    303:      load('styler.js');
                    304:      // load('updater.js'); // would need cross-site XHR
                    305:      load('dfn.js'); // doesn't support split-out specs, but, oh well.
                    306:      // load('status.js'); // would need cross-site XHR
                    307:      if (getCookie('profile') == '1')
                    308:        document.getElementsByTagName('h2')[0].textContent += '; load: ' + (new Date() - loadTimer) + 'ms';
                    309:      fixBrokenLink();
                    310:    }
1.7       mike      311:   </script><link href="http://www.w3.org/StyleSheets/TR/W3C-ED" rel="stylesheet" type="text/css">
1.1       mike      312:   <script src="link-fixup.js"></script>
                    313:   <link href="embedded-content-1.html" title="4.8 Embedded content" rel="prev">
                    314:   <link href="spec.html#contents" title="Table of contents" rel="index">
                    315:   <link href="video.html" title="4.8.6 The video element" rel="next">
                    316:   </head><body onload="fixBrokenLink(); init()"><div class="head" id="head">
                    317:    <p><a href="http://www.w3.org/"><img alt="W3C" height="48" src="http://www.w3.org/Icons/w3c_home" width="72"></a></p>
1.3       mike      318: 
1.1       mike      319:    <h1>HTML5</h1>
                    320:    </div><div>
                    321:    <a href="embedded-content-1.html">&#8592; 4.8 Embedded content</a> &#8211;
                    322:    <a href="spec.html#contents">Table of contents</a> &#8211;
                    323:    <a href="video.html">4.8.6 The video element &#8594;</a>
                    324:   <ol class="toc"><li><ol><li><ol><li><a href="the-iframe-element.html#the-iframe-element"><span class="secno">4.8.2 </span>The <code>iframe</code> element</a></li><li><a href="the-iframe-element.html#the-embed-element"><span class="secno">4.8.3 </span>The <code>embed</code> element</a></li><li><a href="the-iframe-element.html#the-object-element"><span class="secno">4.8.4 </span>The <code>object</code> element</a></li><li><a href="the-iframe-element.html#the-param-element"><span class="secno">4.8.5 </span>The <code>param</code> element</a></li></ol></li></ol></li></ol></div>
                    325: 
                    326:   <h4 id="the-iframe-element"><span class="secno">4.8.2 </span>The <dfn><code>iframe</code></dfn> element</h4><p class="XXX annotation"><b>Status: </b><i>Last call for comments. </i><span><a href="http://www.w3.org/html/wg/tracker/issues/100">ISSUE-100</a> (srcdoc) and <a href="http://www.w3.org/html/wg/tracker/issues/103">ISSUE-103</a> (srcdoc-xml-escaping) block progress to Last Call</span></p><dl class="element"><dt>Categories</dt>
                    327:    <dd><a href="content-models.html#flow-content">Flow content</a>.</dd>
                    328:    <dd><a href="content-models.html#phrasing-content">Phrasing content</a>.</dd>
                    329:    <dd><a href="content-models.html#embedded-content">Embedded content</a>.</dd>
                    330:    <dd><a href="content-models.html#interactive-content">Interactive content</a>.</dd>
                    331:    <dt>Contexts in which this element may be used:</dt>
                    332:    <dd>Where <a href="content-models.html#embedded-content">embedded content</a> is expected.</dd>
                    333:    <dt>Content model:</dt>
                    334:    <dd>Text that conforms to the requirements given in the prose.</dd>
                    335:    <dt>Content attributes:</dt>
                    336:    <dd><a href="elements.html#global-attributes">Global attributes</a></dd>
                    337:    <dd><code title="attr-iframe-src"><a href="#attr-iframe-src">src</a></code></dd>
                    338:    <dd><code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code></dd>
                    339:    <dd><code title="attr-iframe-name"><a href="#attr-iframe-name">name</a></code></dd>
                    340:    <dd><code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code></dd>
                    341:    <dd><code title="attr-iframe-seamless"><a href="#attr-iframe-seamless">seamless</a></code></dd>
                    342:    <dd><code title="attr-dim-width"><a href="the-map-element.html#attr-dim-width">width</a></code></dd>
                    343:    <dd><code title="attr-dim-height"><a href="the-map-element.html#attr-dim-height">height</a></code></dd>
                    344:    <dt>DOM interface:</dt>
                    345:    <dd>
                    346: <pre class="idl">interface <dfn id="htmliframeelement">HTMLIFrameElement</dfn> : <a href="elements.html#htmlelement">HTMLElement</a> {
                    347:            attribute DOMString <a href="#dom-iframe-src" title="dom-iframe-src">src</a>;
                    348:            attribute DOMString <a href="#dom-iframe-srcdoc" title="dom-iframe-srcdoc">srcdoc</a>;
                    349:            attribute DOMString <a href="#dom-iframe-name" title="dom-iframe-name">name</a>;
                    350:   [PutForwards=<a href="common-dom-interfaces.html#dom-domsettabletokenlist-value" title="dom-DOMSettableTokenList-value">value</a>] readonly attribute <a href="common-dom-interfaces.html#domsettabletokenlist">DOMSettableTokenList</a> <a href="#dom-iframe-sandbox" title="dom-iframe-sandbox">sandbox</a>;
                    351:            attribute boolean <a href="#dom-iframe-seamless" title="dom-iframe-seamless">seamless</a>;
                    352:            attribute DOMString <a href="the-map-element.html#dom-dim-width" title="dom-dim-width">width</a>;
                    353:            attribute DOMString <a href="the-map-element.html#dom-dim-height" title="dom-dim-height">height</a>;
                    354:   readonly attribute Document <a href="#dom-iframe-contentdocument" title="dom-iframe-contentDocument">contentDocument</a>;
                    355:   readonly attribute <a href="browsers.html#windowproxy">WindowProxy</a> <a href="#dom-iframe-contentwindow" title="dom-iframe-contentWindow">contentWindow</a>;
                    356: };</pre>
                    357:    </dd>
                    358:   </dl><p>The <code><a href="#the-iframe-element">iframe</a></code> element <a href="rendering.html#represents">represents</a> a
                    359:   <a href="browsers.html#nested-browsing-context">nested browsing context</a>.</p><p>The <dfn id="attr-iframe-src" title="attr-iframe-src"><code>src</code></dfn> attribute
                    360:   gives the address of a page that the <a href="browsers.html#nested-browsing-context">nested browsing
                    361:   context</a> is to contain. The attribute, if present, must be a
                    362:   <a href="urls.html#valid-non-empty-url-potentially-surrounded-by-spaces">valid non-empty URL potentially surrounded by
                    363:   spaces</a>.</p><p>The <dfn id="attr-iframe-srcdoc" title="attr-iframe-srcdoc"><code>srcdoc</code></dfn>
                    364:   attribute gives the content of the page that the <a href="browsers.html#nested-browsing-context">nested
                    365:   browsing context</a> is to contain.  The value of the attribute
                    366:   in is <dfn id="an-iframe-srcdoc-document">an <code>iframe</code> <code title="attr-iframe-srcdoc">srcdoc</code> document</dfn>.</p><p>For <code><a href="#the-iframe-element">iframe</a></code> elements in <a href="dom.html#html-documents">HTML documents</a>,
                    367:   the attribute, if present, must have a value using <a href="syntax.html#syntax">the HTML
                    368:   syntax</a> that consists of the following syntactic components,
                    369:   in the given order:</p><ol><li>Any number of <a href="syntax.html#syntax-comments" title="syntax-comments">comments</a> and
                    370:    <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
                    371: 
                    372:    <li>Optionally, a <a href="syntax.html#syntax-doctype" title="syntax-doctype">DOCTYPE</a>.
                    373: 
                    374:    </li><li>Any number of <a href="syntax.html#syntax-comments" title="syntax-comments">comments</a> and
                    375:    <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
                    376: 
                    377:    <li>The root element, in the form of an <code><a href="semantics.html#the-html-element-0">html</a></code> <a href="syntax.html#syntax-elements" title="syntax-elements">element</a>.</li>
                    378: 
                    379:    <li>Any number of <a href="syntax.html#syntax-comments" title="syntax-comments">comments</a> and
                    380:    <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a>.</li>
                    381: 
                    382:   </ol><p>For <code><a href="#the-iframe-element">iframe</a></code> elements in <a href="dom.html#xml-documents">XML documents</a>,
                    383:   the attribute, if present, must have a value that matches the
                    384:   production labeled <code><a href="infrastructure.html#document">document</a></code> in the XML
                    385:   specification. <a href="references.html#refsXML">[XML]</a></p><p>If the <code title="attr-iframe-src"><a href="#attr-iframe-src">src</a></code> attribute and the
                    386:   <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code> attribute are both
                    387:   specified together, the <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code>
                    388:   attribute takes priority. This allows authors to provide a fallback
                    389:   <a href="urls.html#url">URL</a> for legacy user agents that do not support the
                    390:   <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code> attribute.</p><div class="impl">
                    391: 
                    392:   <p>When an <code><a href="#the-iframe-element">iframe</a></code> element is first <a href="infrastructure.html#insert-an-element-into-a-document" title="insert
                    393:   an element into a document">inserted into a document</a>, the
                    394:   user agent must create a <a href="browsers.html#nested-browsing-context">nested browsing context</a>, and
                    395:   then <a href="#process-the-iframe-attributes">process the <code>iframe</code> attributes</a> for the
                    396:   first time.</p>
                    397: 
                    398:   <p>Whenever an <code><a href="#the-iframe-element">iframe</a></code> element with a <a href="browsers.html#nested-browsing-context">nested
                    399:   browsing context</a> has its <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code> attribute set or changed,
                    400:   the user agent must <a href="#process-the-iframe-attributes">process the <code>iframe</code>
                    401:   attributes</a>.</p>
                    402: 
                    403:   <p>Similarly, whenever an <code><a href="#the-iframe-element">iframe</a></code> element with a
                    404:   <a href="browsers.html#nested-browsing-context">nested browsing context</a> but with no <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code> attribute specified has its
                    405:   <code title="attr-iframe-src"><a href="#attr-iframe-src">src</a></code> attribute set or changed,
                    406:   the user agent must <a href="#process-the-iframe-attributes">process the <code>iframe</code>
                    407:   attributes</a>.</p> <!-- It doesn't happen when the base URL is
                    408:   changed, though. -->
                    409: 
                    410:   <p>When the user agent is to <dfn id="process-the-iframe-attributes">process the <code>iframe</code>
                    411:   attributes</dfn>, it must run the first appropriate steps from the
                    412:   following list:</p>
                    413: 
                    414:   <dl class="switch"><dt>If the <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code> attribute
                    415:    is specified</dt>
                    416: 
                    417:    <dd><p><a href="history.html#navigate">Navigate</a> the element's <a href="browsers.html#browsing-context">browsing
                    418:    context</a> to a resource whose <a href="fetching-resources.html#content-type">Content-Type</a> is
                    419:    <code><a href="iana.html#text-html">text/html</a></code>, whose <a href="urls.html#url">URL</a> is
                    420:    <code><a href="urls.html#about:srcdoc">about:srcdoc</a></code>, and whose data consists of the value of
                    421:    the attribute.</p></dd>
                    422: 
                    423:    <dt>If the <code title="attr-iframe-src"><a href="#attr-iframe-src">src</a></code>
                    424:    attribute is specified but the <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code> attribute is not</dt>
                    425: 
                    426:    <dd>
                    427: 
                    428:     <ol><li><p>If the value of the <code title="attr-iframe-src"><a href="#attr-iframe-src">src</a></code> attribute is the empty string,
                    429:      jump to the <i title="">empty</i> step below.</p></li>
                    430: 
                    431:      <li><p><a href="urls.html#resolve-a-url" title="resolve a url">Resolve</a> the value of
                    432:      the <code title="attr-iframe-src"><a href="#attr-iframe-src">src</a></code> attribute, relative
                    433:      to the <code><a href="#the-iframe-element">iframe</a></code> element.</p></li>
                    434: 
                    435:      <li><p>If that is not successful, then jump to the <i title="">empty</i> step below.</p></li>
                    436: 
                    437:      <li><p>If the resulting <a href="urls.html#absolute-url">absolute URL</a> is an
                    438:      <a href="infrastructure.html#ascii-case-insensitive">ASCII case-insensitive</a> match for the string
                    439:      "<code><a href="fetching-resources.html#about:blank">about:blank</a></code>", and the user agent is processing this
                    440:      <code><a href="#the-iframe-element">iframe</a></code>'s attributes for the first time, then jump to
                    441:      the <i title="">empty</i> step below. (In cases other than the
                    442:      first time, <code><a href="fetching-resources.html#about:blank">about:blank</a></code> is loaded
                    443:      normally.)</p></li>
                    444: 
                    445:      <li><p><a href="history.html#navigate">Navigate</a> the element's <a href="browsers.html#browsing-context">browsing
                    446:      context</a> to the resulting <a href="urls.html#absolute-url">absolute
                    447:      URL</a>.</p></li>
                    448: 
                    449:     </ol><p><i>Empty</i>: When the steps above require the user agent to
                    450:     jump to the <i title="">empty</i> step, if the user agent is
                    451:     processing this <code><a href="#the-iframe-element">iframe</a></code>'s attributes for the first
                    452:     time, then the user agent must <a href="webappapis.html#queue-a-task">queue a task</a> to
                    453:     <a href="webappapis.html#fire-a-simple-event">fire a simple event</a> named <code title="event-load">load</code> at the <code><a href="#the-iframe-element">iframe</a></code>
                    454:     element. (After jumping to this step, the above steps are not
                    455:     resumed.)</p>
                    456: 
                    457:    </dd>
                    458: 
                    459:    <dt>Otherwise</dt>
                    460: 
                    461:    <dd>
                    462: 
                    463:     <p><a href="webappapis.html#queue-a-task">Queue a task</a> to <a href="webappapis.html#fire-a-simple-event">fire a simple event</a>
                    464:     named <code title="event-load">load</code> at the
                    465:     <code><a href="#the-iframe-element">iframe</a></code> element.</p>
                    466: 
                    467:    </dd>
                    468: 
                    469:   </dl><p>Any <a href="history.html#navigate" title="navigate">navigation</a> required of the user
                    470:   agent in the <a href="#process-the-iframe-attributes">process the <code>iframe</code> attributes</a>
                    471:   algorithm must be completed with the <code><a href="#the-iframe-element">iframe</a></code> element's
                    472:   document's <a href="browsers.html#browsing-context">browsing context</a> as the <a href="history.html#source-browsing-context">source
                    473:   browsing context</a>.</p>
                    474: 
1.8       mike      475:   <p>Furthermore, if the <a href="browsers.html#browsing-context">browsing context</a>'s <a href="history.html#session-history">session
                    476:   history</a> contained only one <code><a href="infrastructure.html#document">Document</a></code> when the
                    477:   <a href="#process-the-iframe-attributes">process the <code>iframe</code> attributes</a> algorithm
                    478:   was invoked, and that was the <code><a href="fetching-resources.html#about:blank">about:blank</a></code>
                    479:   <code><a href="infrastructure.html#document">Document</a></code> created when the <a href="browsers.html#browsing-context">browsing context</a>
                    480:   was created, then any <a href="history.html#navigate" title="navigate">navigation</a>
                    481:   required of the user agent in that algorithm must be completed with
                    482:   <a href="history.html#replacement-enabled">replacement enabled</a>.</p> <!-- see also the note near
                    483:   similar text for the location.assign() method -->
1.1       mike      484: 
                    485:   </div><p class="note">If, when the element is created, the <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code> attribute is not set, and
                    486:   the <code title="attr-iframe-src"><a href="#attr-iframe-src">src</a></code> attribute is either
                    487:   also not set or set but its value cannot be <a href="urls.html#resolve-a-url" title="resolve a
                    488:   url">resolved</a>, the browsing context will remain at the
                    489:   initial <code><a href="fetching-resources.html#about:blank">about:blank</a></code> page.</p><p class="note">If the user <a href="history.html#navigate" title="navigate">navigates</a>
                    490:   away from this page, the <code><a href="#the-iframe-element">iframe</a></code>'s corresponding
                    491:   <code><a href="browsers.html#windowproxy">WindowProxy</a></code> object will proxy new <code><a href="browsers.html#window">Window</a></code>
1.9       mike      492:   objects for new <code><a href="infrastructure.html#document">Document</a></code> objects, but the <code title="attr-iframe-src"><a href="#attr-iframe-src">src</a></code> attribute will not change.</p><div class="impl">
                    493: 
                    494:   <div class="note">
                    495: 
                    496:    <p><a href="infrastructure.html#remove-an-element-from-a-document" title="remove an element from a document">Removing</a>
                    497:    an <code><a href="#the-iframe-element">iframe</a></code> from a <code><a href="infrastructure.html#document">Document</a></code> does not cause
                    498:    its <a href="browsers.html#browsing-context">browsing context</a> to be discarded. Indeed, an
                    499:    <code><a href="#the-iframe-element">iframe</a></code>'s <a href="browsers.html#browsing-context">browsing context</a> can survive its
                    500:    original parent <code><a href="infrastructure.html#document">Document</a></code> if its <code><a href="#the-iframe-element">iframe</a></code> is
                    501:    moved to another <code><a href="infrastructure.html#document">Document</a></code>.</p>
                    502: 
1.10      mike      503:    <p>On the other hand, if an <code><a href="#the-iframe-element">iframe</a></code> is <a href="infrastructure.html#remove-an-element-from-a-document" title="remove an element from a document">removed</a> from a
                    504:    <code><a href="infrastructure.html#document">Document</a></code> and is then subsequently garbage collected,
                    505:    this will likely mean (in the absence of other references) that the
                    506:    <a href="browsers.html#child-browsing-context">child browsing context</a>'s <code><a href="browsers.html#windowproxy">WindowProxy</a></code>
                    507:    object will become eligble for garbage collection, which will then
                    508:    lead to that <a href="browsers.html#browsing-context">browsing context</a> being <a href="browsers.html#a-browsing-context-is-discarded" title="a
                    509:    browsing context is discarded">discarded</a>, which will then
                    510:    lead to its <code><a href="infrastructure.html#document">Document</a></code> being <a href="browsers.html#discard-a-document" title="discard a
1.9       mike      511:    document">discarded</a> also. This happens without notice to any
                    512:    scripts running in that <code><a href="infrastructure.html#document">Document</a></code>; for example, no
                    513:    <code title="event-unload">unload</code> events are fired (the
1.10      mike      514:    "<a href="history.html#unload-a-document">unload a document</a>" steps are not run).</p>
1.9       mike      515: 
                    516:   </div>
                    517: 
                    518:   </div><div class="example">
1.1       mike      519: 
                    520:    <p>Here a blog uses the <code title="attr-iframe-srcdoc"><a href="#attr-iframe-srcdoc">srcdoc</a></code> attribute in conjunction
                    521:    with the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> and <code title="attr-iframe-seamless"><a href="#attr-iframe-seamless">seamless</a></code> attributes described
                    522:    below to provide users of user agents that support this feature
                    523:    with an extra layer of protection from script injection in the blog
                    524:    post comments:</p>
                    525: 
                    526:    <pre>&lt;article&gt;
                    527:  &lt;h1&gt;I got my own magazine!&lt;/h1&gt;
                    528:  &lt;p&gt;After much effort, I've finally found a publisher, and so now I
                    529:  have my own magazine! Isn't that awesome?! The first issue will come
                    530:  out in September, and we have articles about getting food, and about
                    531:  getting in boxes, it's going to be great!&lt;/p&gt;
                    532:  &lt;footer&gt;
                    533:   &lt;p&gt;Written by &lt;a href="/users/cap"&gt;cap&lt;/a&gt;.
                    534:   &lt;time pubdate&gt;2009-08-21T23:32Z&lt;/time&gt;&lt;/p&gt;
                    535:  &lt;/footer&gt;
                    536:  &lt;article&gt;
                    537:   &lt;footer&gt; At &lt;time pubdate&gt;2009-08-21T23:35Z&lt;/time&gt;, &lt;a href="/users/ch"&gt;ch&lt;/a&gt; writes: &lt;/footer&gt;
                    538:   &lt;iframe seamless sandbox="allow-same-origin" srcdoc="&lt;p&gt;did you get a cover picture yet?"&gt;&lt;/iframe&gt;
                    539:  &lt;/article&gt;
                    540:  &lt;article&gt;
                    541:   &lt;footer&gt; At &lt;time pubdate&gt;2009-08-21T23:44Z&lt;/time&gt;, &lt;a href="/users/cap"&gt;cap&lt;/a&gt; writes: &lt;/footer&gt;
                    542:   &lt;iframe seamless sandbox="allow-same-origin" srcdoc="&lt;p&gt;Yeah, you can see it &lt;a href=&amp;quot;/gallery?mode=cover&amp;amp;amp;page=1&amp;quot;&gt;in my gallery&lt;/a&gt;."&gt;&lt;/iframe&gt;
                    543:  &lt;/article&gt;
                    544:  &lt;article&gt;
                    545:   &lt;footer&gt; At &lt;time pubdate&gt;2009-08-21T23:58Z&lt;/time&gt;, &lt;a href="/users/ch"&gt;ch&lt;/a&gt; writes: &lt;/footer&gt;
                    546:   &lt;iframe seamless sandbox="allow-same-origin" srcdoc="&lt;p&gt;hey that's earl's table.
                    547: &lt;p&gt;you should get earl&amp;amp;amp;me on the next cover."&gt;&lt;/iframe&gt;
                    548:  &lt;/article&gt;</pre>
                    549: 
                    550:    <p>Notice the way that quotes have to be escaped (otherwise the
                    551:    <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute would
                    552:    end prematurely), and the way raw ampersands (e.g. in URLs or in
                    553:    prose) mentioned in the sandboxed content have to be
                    554:    <em>doubly</em> escaped &#8212; once so that the ampersand is
                    555:    preserved when originally parsing the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute, and once more
                    556:    to prevent the ampersand from being misinterpreted when parsing the
                    557:    sandboxed content.</p>
                    558: 
                    559:   </div><p class="note">In <a href="syntax.html#syntax">the HTML syntax</a>, authors need only
                    560:   remember to use U+0022 QUOTATION MARK characters (") to wrap the
                    561:   attribute contents and then to escape all U+0022 QUOTATION MARK (")
                    562:   and U+0026 AMPERSAND (&amp;) characters, and to specify the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute, to ensure safe
                    563:   embedding of content.</p><p class="note">Due to restrictions of <span>the XML syntax</span>,
                    564:   in XML a number of other characters need to be escaped also to
                    565:   ensure correctness.</p><hr><p>The <dfn id="attr-iframe-name" title="attr-iframe-name"><code>name</code></dfn>
                    566:   attribute, if present, must be a <a href="browsers.html#valid-browsing-context-name">valid browsing context
                    567:   name</a>. The given value is used to name the <a href="browsers.html#nested-browsing-context">nested
                    568:   browsing context</a>. <span class="impl">When the browsing
                    569:   context is created, if the attribute is present, the <a href="browsers.html#browsing-context-name">browsing
                    570:   context name</a> must be set to the value of this attribute;
                    571:   otherwise, the <a href="browsers.html#browsing-context-name">browsing context name</a> must be set to the
                    572:   empty string.</span></p><div class="impl">
                    573: 
                    574:   <p>Whenever the <code title="attr-iframe-name"><a href="#attr-iframe-name">name</a></code> attribute
                    575:   is set, the nested <a href="browsers.html#browsing-context">browsing context</a>'s <a href="browsers.html#browsing-context-name" title="browsing context name">name</a> must be changed to the new
                    576:   value. If the attribute is removed, the <a href="browsers.html#browsing-context-name">browsing context
                    577:   name</a> must be set to the empty string.</p>
                    578: 
                    579:   <p>When content loads in an <code><a href="#the-iframe-element">iframe</a></code>, after any <code title="event-load">load</code> events are fired within the content
                    580:   itself, the user agent must <a href="webappapis.html#queue-a-task">queue a task</a> to <a href="webappapis.html#fire-a-simple-event">fire
                    581:   a simple event</a> named <code title="event-load">load</code> at
                    582:   the <code><a href="#the-iframe-element">iframe</a></code> element. When content whose <a href="urls.html#url">URL</a>
                    583:   has the <a href="origin-0.html#same-origin">same origin</a> as the <code><a href="#the-iframe-element">iframe</a></code>
                    584:   element's <code><a href="infrastructure.html#document">Document</a></code> fails to load (e.g. due to a DNS
                    585:   error, network error, or if the server returned a 4xx or 5xx status
                    586:   code <a href="fetching-resources.html#concept-http-equivalent-codes" title="concept-http-equivalent-codes">or
                    587:   equivalent</a>), then the user agent must <a href="webappapis.html#queue-a-task">queue a
                    588:   task</a> to <a href="webappapis.html#fire-a-simple-event">fire a simple event</a> named <code title="event-error">error</code> at the element instead. (This event
                    589:   does not fire for <a href="parsing.html#parse-error" title="parse error">parse errors</a>,
                    590:   script errors, or any errors for cross-origin resources.)</p>
                    591: 
                    592:   <p>The <a href="webappapis.html#task-source">task source</a> for these <a href="webappapis.html#concept-task" title="concept-task">tasks</a> is the <a href="webappapis.html#dom-manipulation-task-source">DOM manipulation
                    593:   task source</a>.</p>
                    594: 
                    595:   <p class="note">A <code title="event-load">load</code> event is also
                    596:   fired at the <code><a href="#the-iframe-element">iframe</a></code> element when it is created if no
                    597:   other data is loaded in it.</p>
                    598: 
                    599:   <p>When there is an <a href="dom.html#active-parser">active parser</a> in the
                    600:   <code><a href="#the-iframe-element">iframe</a></code>, and when anything in the <code><a href="#the-iframe-element">iframe</a></code> is
                    601:   <a href="the-end.html#delay-the-load-event" title="delay the load event">delaying the load event</a> of
                    602:   the <code><a href="#the-iframe-element">iframe</a></code>'s <a href="browsers.html#browsing-context">browsing context</a>'s
                    603:   <a href="browsers.html#active-document">active document</a>, the <code><a href="#the-iframe-element">iframe</a></code> must
                    604:   <a href="the-end.html#delay-the-load-event">delay the load event</a> of its document.</p>
                    605: 
                    606:   <p class="note">If, during the handling of the <code title="event-load">load</code> event, the <a href="browsers.html#browsing-context">browsing
                    607:   context</a> in the <code><a href="#the-iframe-element">iframe</a></code> is again <a href="history.html#navigate" title="navigate">navigated</a>, that will further <a href="the-end.html#delay-the-load-event">delay the
                    608:   load event</a>.</p>
                    609: 
                    610:   </div><hr><p>The <dfn id="attr-iframe-sandbox" title="attr-iframe-sandbox"><code>sandbox</code></dfn>
                    611:   attribute, when specified, enables a set of extra restrictions on
                    612:   any content hosted by the <code><a href="#the-iframe-element">iframe</a></code>. Its value must be an
                    613:   <a href="common-microsyntaxes.html#unordered-set-of-unique-space-separated-tokens">unordered set of unique space-separated tokens</a>. The
                    614:   allowed values are <code title="attr-iframe-sandbox-allow-same-origin"><a href="#attr-iframe-sandbox-allow-same-origin">allow-same-origin</a></code>,
                    615:   <code title="attr-iframe-sandbox-allow-top-navigation"><a href="#attr-iframe-sandbox-allow-top-navigation">allow-top-navigation</a></code>,
                    616:   <code title="attr-iframe-sandbox-allow-forms"><a href="#attr-iframe-sandbox-allow-forms">allow-forms</a></code>,
                    617:   and <code title="attr-iframe-sandbox-allow-scripts"><a href="#attr-iframe-sandbox-allow-scripts">allow-scripts</a></code>. When
                    618:   the attribute is set, the content is treated as being from a unique
                    619:   <a href="origin-0.html#origin">origin</a>, forms and scripts are disabled, links are
                    620:   prevented from targeting other <a href="browsers.html#browsing-context" title="browsing
                    621:   context">browsing contexts</a>, and plugins are disabled. The
                    622:   <code title="attr-iframe-sandbox-allow-same-origin"><a href="#attr-iframe-sandbox-allow-same-origin">allow-same-origin</a></code>
                    623:   keyword allows the content to be treated as being from the same
                    624:   origin instead of forcing it into a unique origin, the <code title="attr-iframe-sandbox-allow-top-navigation"><a href="#attr-iframe-sandbox-allow-top-navigation">allow-top-navigation</a></code>
                    625:   keyword allows the content to <a href="history.html#navigate">navigate</a> its
                    626:   <a href="browsers.html#top-level-browsing-context">top-level browsing context</a>, and the <code title="attr-iframe-sandbox-allow-forms"><a href="#attr-iframe-sandbox-allow-forms">allow-forms</a></code> and <code title="attr-iframe-sandbox-allow-scripts"><a href="#attr-iframe-sandbox-allow-scripts">allow-scripts</a></code>
                    627:   keywords re-enable forms and scripts respectively (though scripts
                    628:   are still prevented from creating popups).</p><p class="warning">Setting both the <code title="attr-iframe-sandbox-allow-scripts"><a href="#attr-iframe-sandbox-allow-scripts">allow-scripts</a></code> and
                    629:   <code title="attr-iframe-sandbox-allow-same-origin"><a href="#attr-iframe-sandbox-allow-same-origin">allow-same-origin</a></code>
                    630:   keywords together when the embedded page has the <a href="origin-0.html#same-origin">same
                    631:   origin</a> as the page containing the <code><a href="#the-iframe-element">iframe</a></code> allows
                    632:   the embedded page to simply remove the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute.</p><p class="warning">Sandboxing hostile content is of minimal help if
                    633:   an attacker can convince the user to just visit the hostile content
                    634:   directly, rather than in the <code><a href="#the-iframe-element">iframe</a></code>. To limit the
                    635:   damage that can be caused by hostile HTML content, it should be
                    636:   served using the <code><a href="iana.html#text-html-sandboxed">text/html-sandboxed</a></code> MIME type.</p><div class="impl">
                    637: 
                    638:   <!-- v2: Add a new attribute that enables new restrictions, e.g.:
                    639:        - disallow cross-origin loads of any kind (networking
                    640:          override that only allows same-origin URLs or about:,
                    641:          javascript:, data:)
                    642:        - block access to 'parent.frames' from sandbox
                    643:   -->
                    644: 
                    645:   <p>While the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code>
                    646:   attribute is specified, the <code><a href="#the-iframe-element">iframe</a></code> element's
                    647:   <a href="browsers.html#nested-browsing-context">nested browsing context</a> must have the flags given in
                    648:   the following list set.  In addition, any browsing contexts <a href="browsers.html#nested-browsing-context" title="nested browsing context">nested</a> within an
                    649:   <code><a href="#the-iframe-element">iframe</a></code>, either directly or indirectly, must have all
                    650:   the flags set on them as were set on the <code><a href="#the-iframe-element">iframe</a></code>'s
                    651:   <code><a href="infrastructure.html#document">Document</a></code>'s <a href="browsers.html#browsing-context">browsing context</a> when the
                    652:   <code><a href="#the-iframe-element">iframe</a></code>'s <code><a href="infrastructure.html#document">Document</a></code> was created.</p>
                    653: 
                    654:   <dl><dt>The <dfn id="sandboxed-navigation-browsing-context-flag">sandboxed navigation browsing context flag</dfn></dt>
                    655: 
                    656:    <dd>
                    657: 
                    658:     <p>This flag <a href="history.html#sandboxLinks">prevents content from
                    659:     navigating browsing contexts other than the sandboxed browsing
                    660:     context itself</a> (or browsing contexts further nested inside
                    661:     it), and the <a href="browsers.html#top-level-browsing-context">top-level browsing context</a> (which is
                    662:     protected by the <a href="#sandboxed-top-level-navigation-browsing-context-flag">sandboxed top-level navigation browsing
                    663:     context flag</a> defined next).</p>
                    664: 
                    665:     <p>This flag also <a href="browsers.html#sandboxWindowOpen">prevents content
                    666:     from creating new auxiliary browsing contexts</a>, e.g. using the
                    667:     <code title="attr-hyperlink-target"><a href="links.html#attr-hyperlink-target">target</a></code> attribute or the
                    668:     <code title="dom-open"><a href="browsers.html#dom-open">window.open()</a></code> method.</p>
                    669: 
                    670:    </dd>
                    671: 
                    672: 
                    673:    <dt>The <dfn id="sandboxed-top-level-navigation-browsing-context-flag">sandboxed top-level navigation browsing context
                    674:    flag</dfn>, unless the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute's value, when
                    675:    <a href="common-microsyntaxes.html#split-a-string-on-spaces" title="split a string on spaces">split on spaces</a>, is
                    676:    found to have the <dfn id="attr-iframe-sandbox-allow-top-navigation" title="attr-iframe-sandbox-allow-top-navigation"><code>allow-top-navigation</code></dfn>
                    677:    keyword set</dt>
                    678: 
                    679:    <dd>
                    680: 
                    681:     <p>This flag <a href="history.html#sandboxLinks">prevents content from
                    682:     navigating their <span>top-level browsing context</span></a>.</p>
                    683: 
                    684:     <p>When the <code title="attr-iframe-sandbox-allow-top-navigation"><a href="#attr-iframe-sandbox-allow-top-navigation">allow-top-navigation</a></code>
                    685:     is set, content can navigate its <a href="browsers.html#top-level-browsing-context">top-level browsing
                    686:     context</a>, but other <a href="browsers.html#browsing-context" title="browsing context">browsing
                    687:     contexts</a> are still protected by the <a href="#sandboxed-navigation-browsing-context-flag">sandboxed
                    688:     navigation browsing context flag</a> defined above.</p>
                    689: 
                    690:    </dd>
                    691: 
                    692: 
                    693:    <dt>The <dfn id="sandboxed-plugins-browsing-context-flag">sandboxed plugins browsing context flag</dfn></dt>
                    694: 
                    695:    <dd>
                    696: 
                    697:     <p>This flag prevents content from instantiating <a href="infrastructure.html#plugin" title="plugin">plugins</a>, whether using <a href="#sandboxPluginEmbed">the <code>embed</code> element</a>, <a href="#sandboxPluginObject">the <code>object</code> element</a>,
                    698:     <a href="obsolete.html#sandboxPluginApplet">the <code>applet</code>
                    699:     element</a>, or through <a href="history.html#sandboxPluginNavigate">navigation</a> of a <a href="browsers.html#nested-browsing-context">nested
                    700:     browsing context</a>.</p>
                    701: 
                    702:    </dd>
                    703: 
                    704: 
                    705:    <dt>The <dfn id="sandboxed-seamless-iframes-flag">sandboxed seamless iframes flag</dfn></dt>
                    706: 
                    707:    <dd>
                    708: 
                    709:     <p>This flag prevents content from using the <code title="attr-iframe-seamless"><a href="#attr-iframe-seamless">seamless</a></code> attribute on
                    710:     descendant <code><a href="#the-iframe-element">iframe</a></code> elements.</p>
                    711: 
                    712:     <p class="note">This prevents a page inserted using the <code title="attr-iframe-sandbox-allow-same-origin"><a href="#attr-iframe-sandbox-allow-same-origin">allow-same-origin</a></code>
                    713:     keyword from using a CSS-selector-based method of probing the DOM
                    714:     of other pages on the same site (in particular, pages that contain
                    715:     user-sensitive information).</p>
                    716: 
                    717:     <!-- http://lists.w3.org/Archives/Public/public-web-security/2009Dec/thread.html#msg51 -->
                    718: 
                    719:    </dd>
                    720: 
                    721: 
                    722:    <dt>The <dfn id="sandboxed-origin-browsing-context-flag">sandboxed origin browsing context flag</dfn>, unless
                    723:    the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute's
                    724:    value, when <a href="common-microsyntaxes.html#split-a-string-on-spaces" title="split a string on spaces">split on
                    725:    spaces</a>, is found to have the <dfn id="attr-iframe-sandbox-allow-same-origin" title="attr-iframe-sandbox-allow-same-origin"><code>allow-same-origin</code></dfn>
                    726:    keyword set</dt>
                    727: 
                    728:    <dd>
                    729: 
                    730:     <p>This flag <a href="origin-0.html#sandboxOrigin">forces content into a unique
                    731:     origin</a>, thus preventing it from accessing other content from
                    732:     the same <a href="origin-0.html#origin">origin</a>.</p>
                    733: 
                    734:     <p>This flag also <a href="dom.html#sandboxCookies">prevents script from
                    735:     reading from or writing to the <code title="dom-document-cookie">document.cookie</code> IDL
                    736:     attribute</a>, and blocks access to <code title="dom-localStorage">localStorage</code> and <code title="dom-opendatabase">openDatabase()</code>.
                    737:     
                    738:     <a href="references.html#refsWEBSTORAGE">[WEBSTORAGE]</a>
                    739:     
                    740:     <a href="references.html#refsWEBSQL">[WEBSQL]</a>
                    741:     </p>
                    742: 
                    743:     <div class="note">
                    744: 
                    745:      <p>The <code title="attr-iframe-sandbox-allow-same-origin"><a href="#attr-iframe-sandbox-allow-same-origin">allow-same-origin</a></code>
                    746:      attribute is intended for two cases.</p>
                    747: 
                    748:      <p>First, it can be used to allow content from the same site to
                    749:      be sandboxed to disable scripting, while still allowing access to
                    750:      the DOM of the sandboxed content.</p>
                    751: 
                    752:      <p>Second, it can be used to embed content from a third-party
                    753:      site, sandboxed to prevent that site from opening popup windows,
                    754:      etc, without preventing the embedded page from communicating back
                    755:      to its originating site, using the database APIs to store data,
                    756:      etc.</p>
                    757: 
                    758:     </div>
                    759: 
                    760:    </dd>
                    761: 
                    762: 
                    763:    <dt>The <dfn id="sandboxed-forms-browsing-context-flag">sandboxed forms browsing context flag</dfn>, unless
                    764:    the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute's
                    765:    value, when <a href="common-microsyntaxes.html#split-a-string-on-spaces" title="split a string on spaces">split on
                    766:    spaces</a>, is found to have the <dfn id="attr-iframe-sandbox-allow-forms" title="attr-iframe-sandbox-allow-forms"><code>allow-forms</code></dfn>
                    767:    keyword set</dt>
                    768: 
                    769:    <dd>
                    770: 
                    771:     <p>This flag <a href="association-of-controls-and-forms.html#sandboxSubmitBlocked">blocks form
                    772:     submission</a>.</p>
                    773: 
                    774:    </dd>
                    775: 
                    776: 
                    777:    <dt>The <dfn id="sandboxed-scripts-browsing-context-flag">sandboxed scripts browsing context flag</dfn>, unless
                    778:    the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute's
                    779:    value, when <a href="common-microsyntaxes.html#split-a-string-on-spaces" title="split a string on spaces">split on
                    780:    spaces</a>, is found to have the <dfn id="attr-iframe-sandbox-allow-scripts" title="attr-iframe-sandbox-allow-scripts"><code>allow-scripts</code></dfn>
                    781:    keyword set</dt>
                    782: 
                    783:    <dd>
                    784: 
                    785:     <p>This flag <a href="webappapis.html#sandboxScriptBlocked">blocks script
                    786:     execution</a>.</p>
                    787: 
                    788:    </dd>
                    789: 
                    790: 
                    791:    <dt>The <dfn id="sandboxed-automatic-features-browsing-context-flag">sandboxed automatic features browsing context
                    792:    flag</dfn>, unless the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute's value, when
                    793:    <a href="common-microsyntaxes.html#split-a-string-on-spaces" title="split a string on spaces">split on spaces</a>, is
                    794:    found to have the <code title="attr-iframe-sandbox-allow-scripts"><a href="#attr-iframe-sandbox-allow-scripts">allow-scripts</a></code>
                    795:    keyword (defined above) set</dt>
                    796: 
                    797:    <dd>
                    798: 
                    799:     <p>This flag blocks features that trigger automatically, such as
                    800:     <a href="video.html#attr-media-autoplay" title="attr-media-autoplay">automatically playing a
                    801:     video</a> or <a href="association-of-controls-and-forms.html#attr-fe-autofocus" title="attr-fe-autofocus">automatically
                    802:     focusing a form control</a>. It is relaxed by the same flag as
                    803:     scripts, because when scripts are enabled these features are
                    804:     trivially possible anyway, and it would be unfortunate to force
                    805:     authors to use script to do them when sandboxed rather than
                    806:     allowing them to use the declarative features.</p>
                    807: 
                    808:    </dd>
                    809: 
                    810:   </dl><p>These flags must not be set unless the conditions listed above
                    811:   define them as being set.</p>
                    812: 
                    813:   <p class="warning">These flags only take effect when the
                    814:   <a href="browsers.html#nested-browsing-context">nested browsing context</a> of the <code><a href="#the-iframe-element">iframe</a></code> is
                    815:   <a href="history.html#navigate" title="navigate">navigated</a>. Removing then, or removing
                    816:   the entire <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code>
                    817:   attribute, has no effect on an already-loaded page.</p>
                    818: 
                    819:   </div><div class="example">
                    820: 
                    821:    <p>In this example, some completely-unknown, potentially hostile,
                    822:    user-provided HTML content is embedded in a page. Because it is
                    823:    sandboxed, it is treated by the user agent as being from a unique
                    824:    origin, despite the content being served from the same site. Thus
                    825:    it is affected by all the normal cross-site restrictions. In
                    826:    addition, the embedded page has scripting disabled, plugins
                    827:    disabled, forms disabled, and it cannot navigate any frames or
                    828:    windows other than itself (or any frames or windows it itself
                    829:    embeds).</p>
                    830: 
                    831:    <pre>&lt;p&gt;We're not scared of you! Here is your content, unedited:&lt;/p&gt;
                    832: &lt;iframe sandbox src="getusercontent.cgi?id=12193"&gt;&lt;/iframe&gt;</pre>
                    833: 
                    834:    <p>Note that cookies are still sent to the server in the <code title="">getusercontent.cgi</code> request, though they are not
                    835:    visible in the <code title="dom-document-cookie"><a href="dom.html#dom-document-cookie">document.cookie</a></code> IDL
                    836:    attribute.</p>
                    837: 
                    838:    <p class="warning">It is important that the server serve the
                    839:    user-provided HTML using the <code><a href="iana.html#text-html-sandboxed">text/html-sandboxed</a></code> MIME
                    840:    type so that if the attacker convinces the user to visit that page
                    841:    directly, the page doesn't run in the context of the site's origin,
                    842:    which would make the user vulnerable to any attack found in the
                    843:    page.</p>
                    844: 
                    845:   </div><div class="example">
                    846: 
                    847:    <p>In this example, a gadget from another site is embedded. The
                    848:    gadget has scripting and forms enabled, and the origin sandbox
                    849:    restrictions are lifted, allowing the gadget to communicate with
                    850:    its originating server. The sandbox is still useful, however, as it
                    851:    disables plugins and popups, thus reducing the risk of the user
                    852:    being exposed to malware and other annoyances.</p>
                    853: 
                    854:    <pre>&lt;iframe sandbox="allow-same-origin allow-forms allow-scripts"
                    855:         src="http://maps.example.com/embedded.html"&gt;&lt;/iframe&gt;</pre>
                    856: 
                    857:   </div><div class="example">
                    858: 
                    859:    <p>Suppose a file A contained the following fragment:</p>
                    860: 
                    861:    <pre>&lt;iframe sandbox="allow-same-origin allow-forms" src=B&gt;&lt;/iframe&gt;</pre>
                    862: 
                    863:    <p>Suppose that file B contained an iframe also:</p>
                    864: 
                    865:    <pre>&lt;iframe sandbox="allow-scripts" src=C&gt;&lt;/iframe&gt;</pre>
                    866: 
                    867:    <p>Further, suppose that file C contained a link:</p>
                    868: 
                    869:    <pre>&lt;a href=D&gt;Link&lt;/a&gt;</pre>
                    870: 
                    871:    <p>For this example, suppose all the files were served as
                    872:    <code><a href="iana.html#text-html">text/html</a></code>.</p>
                    873: 
                    874:    <p>Page C in this scenario has all the sandboxing flags
                    875:    set. Scripts are disabled, because the <code><a href="#the-iframe-element">iframe</a></code> in A has
                    876:    scripts disabled, and this overrides the <code title="attr-iframe-sandbox-allow-scripts"><a href="#attr-iframe-sandbox-allow-scripts">allow-scripts</a></code>
                    877:    keyword set on the <code><a href="#the-iframe-element">iframe</a></code> in B. Forms are also
                    878:    disabled, because the inner <code><a href="#the-iframe-element">iframe</a></code> (in B) does not
                    879:    have the <code title="attr-iframe-sandbox-allow-forms"><a href="#attr-iframe-sandbox-allow-forms">allow-forms</a></code> keyword
                    880:    set.</p>
                    881: 
                    882:    <p>Suppose now that a script in A removes all the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attributes in A and
                    883:    B. This would change nothing immediately. If the user clicked the
                    884:    link in C, loading page D into the <code><a href="#the-iframe-element">iframe</a></code> in B, page D
                    885:    would now act as if the <code><a href="#the-iframe-element">iframe</a></code> in B had the <code title="attr-iframe-sandbox-allow-same-origin"><a href="#attr-iframe-sandbox-allow-same-origin">allow-same-origin</a></code>
                    886:    and <code title="attr-iframe-sandbox-allow-forms"><a href="#attr-iframe-sandbox-allow-forms">allow-forms</a></code> keywords
                    887:    set, because that was the state of the <a href="browsers.html#nested-browsing-context">nested browsing
                    888:    context</a> in the <code><a href="#the-iframe-element">iframe</a></code> in A when page B was
                    889:    loaded.</p>
                    890: 
                    891:    <p>Generally speaking, dynamically removing or changing the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute is
                    892:    ill-advised, because it can make it quite hard to reason about what
                    893:    will be allowed and what will not.</p>
                    894: 
                    895:   </div><p class="note">Potentially hostile files can be served from the
                    896:   same server as the file containing the <code><a href="#the-iframe-element">iframe</a></code> element
                    897:   by labeling them as <code><a href="iana.html#text-html-sandboxed">text/html-sandboxed</a></code> instead of
                    898:   <code><a href="iana.html#text-html">text/html</a></code>. This ensures that scripts in the files are
                    899:   unable to attack the site (as if they were actually served from
                    900:   another server), even if the user is tricked into visiting those
                    901:   pages directly, without the protection of the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute.</p><p class="warning">If the <code title="attr-iframe-sandbox-allow-scripts"><a href="#attr-iframe-sandbox-allow-scripts">allow-scripts</a></code>
                    902:   keyword is set along with <code title="attr-iframe-sandbox-allow-same-origin"><a href="#attr-iframe-sandbox-allow-same-origin">allow-same-origin</a></code>
                    903:   keyword, and the file is from the <a href="origin-0.html#same-origin">same origin</a> as the
                    904:   <code><a href="#the-iframe-element">iframe</a></code>'s <code><a href="infrastructure.html#document">Document</a></code>, then a script in the
                    905:   "sandboxed" iframe could just reach out, remove the <code title="attr-iframe-sandbox"><a href="#attr-iframe-sandbox">sandbox</a></code> attribute, and then
                    906:   reload itself, effectively breaking out of the sandbox
                    907:   altogether.</p><hr><!-- v2: Might be interesting to have a value on seamless that
                    908:   allowed event propagation of some sort, maybe based on the WICD
                    909:   work: http://www.w3.org/TR/WICD/ --><p>The <dfn id="attr-iframe-seamless" title="attr-iframe-seamless"><code>seamless</code></dfn>
                    910:   attribute is a <a href="common-microsyntaxes.html#boolean-attribute">boolean attribute</a>. When specified, it
                    911:   indicates that the <code><a href="#the-iframe-element">iframe</a></code> element's <a href="browsers.html#browsing-context">browsing
                    912:   context</a> is to be rendered in a manner that makes it appear to
                    913:   be part of the containing document (seamlessly included in the
                    914:   parent document). <span class="impl">Specifically, when the
                    915:   attribute is set on an <code><a href="#the-iframe-element">iframe</a></code> element whose owner
                    916:   <code><a href="infrastructure.html#document">Document</a></code>'s <a href="browsers.html#browsing-context">browsing context</a> did not have
                    917:   the <a href="#sandboxed-seamless-iframes-flag">sandboxed seamless iframes flag</a> set when that
                    918:   <code><a href="infrastructure.html#document">Document</a></code> was created, and while either the
                    919:   <a href="browsers.html#browsing-context">browsing context</a>'s <a href="browsers.html#active-document">active document</a> has the
                    920:   <a href="origin-0.html#same-origin">same origin</a> as the <code><a href="#the-iframe-element">iframe</a></code> element's
                    921:   document, or the <a href="browsers.html#browsing-context">browsing context</a>'s <a href="browsers.html#active-document">active
                    922:   document</a>'s <em><a href="dom.html#the-document-s-address" title="the document's
                    923:   address">address</a></em> has the <a href="origin-0.html#same-origin">same origin</a> as the
                    924:   <code><a href="#the-iframe-element">iframe</a></code> element's document, the following requirements
                    925:   apply:</span></p><div class="impl">
                    926: 
1.13    ! mike      927:   <ul><li><p>The user agent must set the <dfn id="seamless-browsing-context-flag">seamless browsing context
        !           928:    flag</dfn> to true for that <a href="browsers.html#browsing-context">browsing context</a>. This
        !           929:    will <a href="history.html#seamlessLinks">cause links to open in the parent
        !           930:    browsing context</a> unless an <a href="browsers.html#explicit-self-navigation-override">explicit self-navigation
        !           931:    override</a> is used (<code title="">target="_self"</code>).</p></li>
1.1       mike      932: 
                    933:    <li><p>In a CSS-supporting user agent: the user agent must add all
                    934:    the style sheets that apply to the <code><a href="#the-iframe-element">iframe</a></code> element to
                    935:    the cascade of the <a href="browsers.html#active-document">active document</a> of the
                    936:    <code><a href="#the-iframe-element">iframe</a></code> element's <a href="browsers.html#nested-browsing-context">nested browsing context</a>,
                    937:    at the appropriate cascade levels, before any style sheets
                    938:    specified by the document itself.</p></li>
                    939: 
                    940:    <li><p>In a CSS-supporting user agent: the user agent must, for the
                    941:    purpose of CSS property inheritance only, treat the root element of
                    942:    the <a href="browsers.html#active-document">active document</a> of the <code><a href="#the-iframe-element">iframe</a></code>
                    943:    element's <a href="browsers.html#nested-browsing-context">nested browsing context</a> as being a child of
                    944:    the <code><a href="#the-iframe-element">iframe</a></code> element. (Thus inherited properties on the
                    945:    root element of the document in the <code><a href="#the-iframe-element">iframe</a></code> will
                    946:    inherit the computed values of those properties on the
                    947:    <code><a href="#the-iframe-element">iframe</a></code> element instead of taking their initial
                    948:    values.)</p></li>
                    949: 
                    950:    <li><p>In visual media, in a CSS-supporting user agent: the user agent
                    951:    should set the intrinsic width of the <code><a href="#the-iframe-element">iframe</a></code> to the
                    952:    width that the element would have if it was a non-replaced
                    953:    block-level element with 'width: auto'.</p></li>
                    954: 
                    955:    <li><p>In visual media, in a CSS-supporting user agent: the user
                    956:    agent should set the intrinsic height of the <code><a href="#the-iframe-element">iframe</a></code> to
                    957:    the height of the bounding box around the content rendered in the
                    958:    <code><a href="#the-iframe-element">iframe</a></code> at its current width (as given in the previous
                    959:    bullet point), as it would be if the scrolling position was such
                    960:    that the top of the viewport for the content rendered in the
                    961:    <code><a href="#the-iframe-element">iframe</a></code> was aligned with the origin of that content's
                    962:    canvas.</p></li>
                    963: 
                    964:    <li>
                    965: 
                    966:     <p>In visual media, in a CSS-supporting user agent: the user agent
                    967:     must force the height of the initial containing block of the
                    968:     <a href="browsers.html#active-document">active document</a> of the <a href="browsers.html#nested-browsing-context">nested browsing
                    969:     context</a> of the <code><a href="#the-iframe-element">iframe</a></code> to zero.</p>
                    970: 
                    971:     <p class="note">This is intended to get around the otherwise
                    972:     circular dependency of percentage dimensions that depend on the
                    973:     height of the containing block, thus affecting the height of the
                    974:     document's bounding box, thus affecting the height of the
                    975:     viewport, thus affecting the size of the initial containing
                    976:     block.</p>
                    977: 
                    978:    </li>
                    979: 
                    980:    <li><p>In speech media, the user agent should render the <a href="browsers.html#nested-browsing-context">nested
                    981:    browsing context</a> without announcing that it is a separate
                    982:    document.</p></li>
                    983: 
                    984:    <li>
                    985: 
                    986:     <p>User agents should, in general, act as if the <a href="browsers.html#active-document">active
                    987:     document</a> of the <code><a href="#the-iframe-element">iframe</a></code>'s <a href="browsers.html#nested-browsing-context">nested browsing
                    988:     context</a> was part of the document that the
                    989:     <code><a href="#the-iframe-element">iframe</a></code> is in.</p>
                    990: 
                    991:     <p class="example">For example if the user agent supports listing
                    992:     all the links in a document, links in "seamlessly" nested
                    993:     documents would be included in that list without being
                    994:     significantly distinguished from links in the document itself.</p>
                    995: 
                    996:    </li>
                    997: 
                    998:   </ul><p>If the attribute is not specified, or if the <a href="origin-0.html#origin">origin</a>
                    999:   conditions listed above are not met, then the user agent should
                   1000:   render the <a href="browsers.html#nested-browsing-context">nested browsing context</a> in a manner that is
                   1001:   clearly distinguishable as a separate <a href="browsers.html#browsing-context">browsing context</a>,
                   1002:   and the <a href="#seamless-browsing-context-flag">seamless browsing context flag</a> must be set to
                   1003:   false for that <a href="browsers.html#browsing-context">browsing context</a>.</p>
                   1004: 
                   1005:   <p class="warning">It is important that user agents recheck the
                   1006:   above conditions whenever the <a href="browsers.html#active-document">active document</a> of the
                   1007:   <a href="browsers.html#nested-browsing-context">nested browsing context</a> of the <code><a href="#the-iframe-element">iframe</a></code>
                   1008:   changes, such that the <a href="#seamless-browsing-context-flag">seamless browsing context flag</a>
                   1009:   gets unset if the <a href="browsers.html#nested-browsing-context">nested browsing context</a> is <a href="history.html#navigate" title="navigate">navigated</a> to another origin.</p>
                   1010: 
                   1011:   </div><p class="note">The attribute can be set or removed dynamically,
                   1012:   with the rendering updating in tandem.</p><div class="example">
                   1013: 
                   1014:    <p>In this example, the site's navigation is embedded using a
                   1015:    client-side include using an <code><a href="#the-iframe-element">iframe</a></code>. Any links in the
                   1016:    <code><a href="#the-iframe-element">iframe</a></code> will, in new user agents, be automatically
                   1017:    opened in the <code><a href="#the-iframe-element">iframe</a></code>'s parent browsing context; for
                   1018:    legacy user agents, the site could also include a <code><a href="semantics.html#the-base-element">base</a></code>
                   1019:    element with a <code title="attr-base-target"><a href="semantics.html#attr-base-target">target</a></code>
                   1020:    attribute with the value <code title="">_parent</code>. Similarly,
                   1021:    in new user agents the styles of the parent page will be
                   1022:    automatically applied to the contents of the frame, but to support
                   1023:    legacy user agents authors might wish to include the styles
                   1024:    explicitly.</p>
                   1025: 
                   1026:    <pre>&lt;nav&gt;&lt;iframe seamless src="nav.include.html"&gt;&lt;/iframe&gt;&lt;/nav&gt;</pre>
                   1027: 
                   1028:   </div><hr><p>The <code><a href="#the-iframe-element">iframe</a></code> element supports <a href="the-map-element.html#dimension-attributes">dimension
                   1029:   attributes</a> for cases where the embedded content has specific
                   1030:   dimensions (e.g. ad units have well-defined dimensions).</p><p>An <code><a href="#the-iframe-element">iframe</a></code> element never has <a href="content-models.html#fallback-content">fallback
                   1031:   content</a>, as it will always create a nested <a href="browsers.html#browsing-context">browsing
                   1032:   context</a>, regardless of whether the specified initial contents
                   1033:   are successfully used.</p><p>Descendants of <code><a href="#the-iframe-element">iframe</a></code> elements represent
                   1034:   nothing. (In legacy user agents that do not support
                   1035:   <code><a href="#the-iframe-element">iframe</a></code> elements, the contents would be parsed as markup
                   1036:   that could act as fallback content.)</p><p>When used in <a href="dom.html#html-documents">HTML documents</a>, the allowed content
                   1037:   model of <code><a href="#the-iframe-element">iframe</a></code> elements is text, except that invoking
                   1038:   the <a href="the-end.html#html-fragment-parsing-algorithm">HTML fragment parsing algorithm</a> with the
                   1039:   <code><a href="#the-iframe-element">iframe</a></code> element as the <var title="">context</var>
                   1040:   element and the text contents as the <var title="">input</var> must
                   1041:   result in a list of nodes that are all <a href="content-models.html#phrasing-content">phrasing
                   1042:   content</a>, with no <a href="parsing.html#parse-error" title="parse error">parse
                   1043:   errors</a> having occurred, with no <code><a href="scripting-1.html#script">script</a></code> elements
                   1044:   being anywhere in the list or as descendants of elements in the
                   1045:   list, and with all the elements in the list (including their
                   1046:   descendants) being themselves conforming.</p><p>The <code><a href="#the-iframe-element">iframe</a></code> element must be empty in <a href="dom.html#xml-documents">XML
                   1047:   documents</a>.</p><p class="note">The <a href="parsing.html#html-parser">HTML parser</a> treats markup inside
                   1048:   <code><a href="#the-iframe-element">iframe</a></code> elements as text.</p><div class="impl">
                   1049: 
                   1050:   <p>The IDL attributes <dfn id="dom-iframe-src" title="dom-iframe-src"><code>src</code></dfn>, <dfn id="dom-iframe-srcdoc" title="dom-iframe-srcdoc"><code>srcdoc</code></dfn>, <dfn id="dom-iframe-name" title="dom-iframe-name"><code>name</code></dfn>, <dfn id="dom-iframe-sandbox" title="dom-iframe-sandbox"><code>sandbox</code></dfn>, and <dfn id="dom-iframe-seamless" title="dom-iframe-seamless"><code>seamless</code></dfn> must
                   1051:   <a href="common-dom-interfaces.html#reflect">reflect</a> the respective content attributes of the same
                   1052:   name.</p>
                   1053: 
                   1054:   <p>The <dfn id="dom-iframe-contentdocument" title="dom-iframe-contentDocument"><code>contentDocument</code></dfn>
                   1055:   IDL attribute must return the <code><a href="infrastructure.html#document">Document</a></code> object of the
                   1056:   <a href="browsers.html#active-document">active document</a> of the <code><a href="#the-iframe-element">iframe</a></code> element's
                   1057:   <a href="browsers.html#nested-browsing-context">nested browsing context</a>.</p>
                   1058: 
                   1059:   <p>The <dfn id="dom-iframe-contentwindow" title="dom-iframe-contentWindow"><code>contentWindow</code></dfn>
                   1060:   IDL attribute must return the <code><a href="browsers.html#windowproxy">WindowProxy</a></code> object of the
                   1061:   <code><a href="#the-iframe-element">iframe</a></code> element's <a href="browsers.html#nested-browsing-context">nested browsing
                   1062:   context</a>.</p>
                   1063: 
                   1064:   </div><div class="example">
                   1065: 
                   1066:    <p>Here is an example of a page using an <code><a href="#the-iframe-element">iframe</a></code> to
                   1067:    include advertising from an advertising broker:</p>
                   1068: 
                   1069:    <pre>&lt;iframe src="http://ads.example.com/?customerid=923513721&amp;amp;format=banner"
                   1070:         width="468" height="60"&gt;&lt;/iframe&gt;</pre>
                   1071: 
                   1072:   </div><h4 id="the-embed-element"><span class="secno">4.8.3 </span>The <dfn><code>embed</code></dfn> element</h4><p class="XXX annotation"><b>Status: </b><i>Last call for comments</i></p><!-- (v2?)
                   1073:  we have all kinds of quirks we should define if they come up during
                   1074:  testing, as e.g. shown in:
                   1075:  http://mxr.mozilla.org/mozilla-central/source/layout/generic/nsObjectFrame.cpp
                   1076:  http://trac.webkit.org/browser/trunk/WebCore/html/HTMLEmbedElement.cpp
                   1077:  http://trac.webkit.org/browser/trunk/WebCore/rendering/RenderPartObject.cpp (updateWidget)
                   1078:  e.g. - 240x200 default
                   1079:       - the attributes/params are sent in a name/value pair list as follows (for Gecko):
                   1080:          + attributes of the element, in source order
                   1081:          + a synthesised 'src' attribute, if there was no 'src' but
                   1082:            there was a 'data', with the value of the 'data' attribute
                   1083:          + the params, in source order
                   1084:         (WebKit does something different still)
                   1085:       - the HIDDEN attribute (might be moot now)
                   1086: --><dl class="element"><dt>Categories</dt>
                   1087:    <dd><a href="content-models.html#flow-content">Flow content</a>.</dd>
                   1088:    <dd><a href="content-models.html#phrasing-content">Phrasing content</a>.</dd>
                   1089:    <dd><a href="content-models.html#embedded-content">Embedded content</a>.</dd>
                   1090:    <dd><a href="content-models.html#interactive-content">Interactive content</a>.</dd>
                   1091:    <dt>Contexts in which this element may be used:</dt>
                   1092:    <dd>Where <a href="content-models.html#embedded-content">embedded content</a> is expected.</dd>
                   1093:    <dt>Content model:</dt>
                   1094:    <dd>Empty.</dd>
                   1095:    <dt>Content attributes:</dt>
                   1096:    <dd><a href="elements.html#global-attributes">Global attributes</a></dd>
                   1097:    <dd><code title="attr-embed-src"><a href="#attr-embed-src">src</a></code></dd>
                   1098:    <dd><code title="attr-embed-type"><a href="#attr-embed-type">type</a></code></dd>
                   1099:    <dd><code title="attr-dim-width"><a href="the-map-element.html#attr-dim-width">width</a></code></dd>
                   1100:    <dd><code title="attr-dim-height"><a href="the-map-element.html#attr-dim-height">height</a></code></dd>
                   1101:    <dd>Any other attribute that has no namespace (see prose).</dd>
                   1102:    <dt>DOM interface:</dt>
                   1103:    <dd>
                   1104: <pre class="idl">interface <dfn id="htmlembedelement">HTMLEmbedElement</dfn> : <a href="elements.html#htmlelement">HTMLElement</a> {
                   1105:            attribute DOMString <a href="#dom-embed-src" title="dom-embed-src">src</a>;
                   1106:            attribute DOMString <a href="#dom-embed-type" title="dom-embed-type">type</a>;
                   1107:            attribute DOMString <a href="the-map-element.html#dom-dim-width" title="dom-dim-width">width</a>;
                   1108:            attribute DOMString <a href="the-map-element.html#dom-dim-height" title="dom-dim-height">height</a>;
                   1109: };</pre>
                   1110:     <div class="impl">
                   1111:     <p>Depending on the type of content instantiated by the
                   1112:     <code><a href="#the-embed-element">embed</a></code> element, the node may also support other
                   1113:     interfaces.</p>
                   1114:     </div>
                   1115:    </dd>
                   1116:   </dl><p>The <code><a href="#the-embed-element">embed</a></code> element <a href="rendering.html#represents">represents</a> an
                   1117:   integration point for an external (typically non-HTML) application
                   1118:   or interactive content.</p><p>The <dfn id="attr-embed-src" title="attr-embed-src"><code>src</code></dfn> attribute
                   1119:   gives the address of the resource being embedded. The attribute, if
                   1120:   present, must contain a <a href="urls.html#valid-non-empty-url-potentially-surrounded-by-spaces">valid non-empty URL potentially
                   1121:   surrounded by spaces</a>.</p><p>The <dfn id="attr-embed-type" title="attr-embed-type"><code>type</code></dfn>
                   1122:   attribute, if present, gives the <a href="infrastructure.html#mime-type">MIME type</a> by which the
                   1123:   plugin to instantiate is selected. The value must be a <a href="infrastructure.html#valid-mime-type">valid
                   1124:   MIME type</a>. If both the <code title="attr-embed-type"><a href="#attr-embed-type">type</a></code> attribute and the <code title="attr-embed-src"><a href="#attr-embed-src">src</a></code> attribute are present, then the
                   1125:   <code title="attr-embed-type"><a href="#attr-embed-type">type</a></code> attribute must specify the
                   1126:   same type as the <a href="fetching-resources.html#content-type" title="Content-Type">explicit Content-Type
                   1127:   metadata</a> of the resource given by the <code title="attr-embed-src"><a href="#attr-embed-src">src</a></code> attribute.</p><div class="impl">
                   1128: 
                   1129:   <p>When the element is created with neither a <code title="attr-embed-src"><a href="#attr-embed-src">src</a></code> attribute nor a <code title="attr-embed-type"><a href="#attr-embed-type">type</a></code> attribute, and when attributes
                   1130:   are removed such that neither attribute is present on the element
                   1131:   anymore, and when the element has a <a href="video.html#media-element">media element</a>
                   1132:   ancestor, and when the element has an ancestor <code><a href="#the-object-element">object</a></code>
                   1133:   element that is <em>not</em> showing its <a href="content-models.html#fallback-content">fallback
                   1134:   content</a>, any plugins instantiated for the element must be
                   1135:   removed, and the <code><a href="#the-embed-element">embed</a></code> element represents nothing.</p>
                   1136: 
                   1137:   <p id="sandboxPluginEmbed">If either:
                   1138: 
                   1139:   </p><ul><li>the <a href="#sandboxed-plugins-browsing-context-flag">sandboxed plugins browsing context flag</a> was
                   1140:    set on the <a href="browsers.html#browsing-context">browsing context</a> for which the
                   1141:    <code><a href="#the-embed-element">embed</a></code> element's <code><a href="infrastructure.html#document">Document</a></code> is the
                   1142:    <a href="browsers.html#active-document">active document</a> when that <code><a href="infrastructure.html#document">Document</a></code> was
                   1143:    created, or</li>
                   1144: 
                   1145:    <li>the <code><a href="#the-embed-element">embed</a></code> element's <code><a href="infrastructure.html#document">Document</a></code> was
                   1146:    parsed from a resource whose <a href="fetching-resources.html#content-type-sniffing-0" title="Content-Type
                   1147:    sniffing">sniffed type</a> as determined during <a href="history.html#navigate" title="navigate">navigation</a> is
                   1148:    <code><a href="iana.html#text-html-sandboxed">text/html-sandboxed</a></code></li>
                   1149: 
                   1150:   </ul><p>...then the user agent must render the <code><a href="#the-embed-element">embed</a></code> element
                   1151:   in a manner that conveys that the <a href="infrastructure.html#plugin">plugin</a> was
                   1152:   disabled. The user agent may offer the user the option to override
                   1153:   the sandbox and instantiate the <a href="infrastructure.html#plugin">plugin</a> anyway; if the
                   1154:   user invokes such an option, the user agent must act as if the
                   1155:   conditions above did not apply for the purposes of this element.</p>
                   1156: 
                   1157:   <p class="warning">Plugins are disabled in sandboxed browsing
                   1158:   contexts because they might not honor the restrictions imposed by
                   1159:   the sandbox (e.g. they might allow scripting even when scripting in
                   1160:   the sandbox is disabled). User agents should convey the danger of
                   1161:   overriding the sandbox to the user if an option to do so is
                   1162:   provided.</p>
                   1163: 
                   1164:   <p>An <code><a href="#the-embed-element">embed</a></code> element is said to be <dfn id="concept-embed-active" title="concept-embed-active">potentially active</dfn> when the
                   1165:   following conditions are all met simultaneously:</p>
                   1166: 
                   1167:   <ul class="brief"><li>The element is <a href="infrastructure.html#in-a-document" title="in a document">in a <code>Document</code></a>.</li>
                   1168:    <li>The element's <code><a href="infrastructure.html#document">Document</a></code> is <a href="browsers.html#fully-active">fully active</a>.</li>
                   1169:    <li>The element has either a <code title="attr-embed-src"><a href="#attr-embed-src">src</a></code> attribute set or a <code title="attr-embed-type"><a href="#attr-embed-type">type</a></code> attribute set (or both).</li>
                   1170:    <li>The element's <code title="attr-embed-src"><a href="#attr-embed-src">src</a></code> attribute is either absent or its value is the empty string.</li>
                   1171:    <li>The element is not in a <code><a href="infrastructure.html#document">Document</a></code> whose <a href="browsers.html#browsing-context">browsing context</a> had the <a href="#sandboxed-plugins-browsing-context-flag">sandboxed plugins browsing context flag</a> set when the <code><a href="infrastructure.html#document">Document</a></code> was created (unless this has been overridden as described above).</li>
                   1172:    <li>The element's <code><a href="infrastructure.html#document">Document</a></code> was not parsed from a resource whose <a href="fetching-resources.html#content-type-sniffing-0" title="Content-Type sniffing">sniffed type</a> as determined during <a href="history.html#navigate" title="navigate">navigation</a> is <code><a href="iana.html#text-html-sandboxed">text/html-sandboxed</a></code> (unless this has been overridden as described above).</li>
                   1173:    <li>The element is not a descendant of a <a href="video.html#media-element">media element</a>.</li>
                   1174:    <li>The element is not a descendant of an <code><a href="#the-object-element">object</a></code> element that is not showing its <a href="content-models.html#fallback-content">fallback content</a>.</li>
                   1175:   </ul><p>Whenever an <code><a href="#the-embed-element">embed</a></code> element that was not <a href="#concept-embed-active" title="concept-embed-active">potentially active</a> becomes <a href="#concept-embed-active" title="concept-embed-active">potentially active</a>, and whenever
                   1176:   a <a href="#concept-embed-active" title="concept-embed-active">potentially active</a>
                   1177:   <code><a href="#the-embed-element">embed</a></code> element's <code title="attr-embed-type"><a href="#attr-embed-type">src</a></code> attribute is set, changed, or
                   1178:   removed, and whenever a <a href="#concept-embed-active" title="concept-embed-active">potentially active</a>
                   1179:   <code><a href="#the-embed-element">embed</a></code> element's <code title="attr-embed-type"><a href="#attr-embed-type">type</a></code> attribute is set, changed, or
                   1180:   removed, the appropriate set of steps from the following is then
                   1181:   applied:</p>
                   1182: 
                   1183:   <dl class="switch"><dt>If the element has a <code title="attr-embed-src"><a href="#attr-embed-src">src</a></code>
                   1184:    attribute set</dt>
                   1185: 
                   1186:    <dd>
                   1187: 
                   1188:     <p>The user agent must <a href="urls.html#resolve-a-url" title="resolve a url">resolve</a>
                   1189:     the value of the element's <code title="attr-embed-src"><a href="#attr-embed-src">src</a></code>
                   1190:     attribute, relative to the element. If that is successful, the
                   1191:     user agent should <a href="fetching-resources.html#fetch">fetch</a> the resulting <a href="urls.html#absolute-url">absolute
                   1192:     URL</a>, from the element's <a href="browsers.html#browsing-context-scope-origin">browsing context scope
                   1193:     origin</a> if it has one<!-- potentially http-origin privacy
                   1194:     sensitive -->. The <a href="webappapis.html#concept-task" title="concept-task">task</a> that is
                   1195:     <a href="webappapis.html#queue-a-task" title="queue a task">queued</a> by the <a href="webappapis.html#networking-task-source">networking
                   1196:     task source</a> once the resource has been <a href="fetching-resources.html#fetch" title="fetch">fetched</a> must find and instantiate an
                   1197:     appropriate <a href="infrastructure.html#plugin">plugin</a> based on the <a href="#concept-embed-type" title="concept-embed-type">content's type</a>, and hand that
                   1198:     <a href="infrastructure.html#plugin">plugin</a> the content of the resource, replacing any
                   1199:     previously instantiated plugin for the element.</p> <!-- Note that
                   1200:     this doesn't happen when the base URL changes. -->
                   1201: 
                   1202:     <p>Fetching the resource must <a href="the-end.html#delay-the-load-event">delay the load event</a> of
                   1203:     the element's document.</p>
                   1204:     <!-- if we add load/error events, then replace the previous
                   1205:     paragraph with the text one: -->
                   1206:     <!-- similar text in various places -->
                   1207:     <!--<p>Fetching the resource must <span>delay the load
                   1208:     event</span> of the element's document until the final <span
                   1209:     title="concept-task">task</span> that is <span title="queue a
                   1210:     task">queued</span> by the <span>networking task source</span>
                   1211:     once the resource has been <span title="fetch">fetched</span> has
                   1212:     been run.</p>-->
                   1213: 
                   1214:    </dd>
                   1215: 
                   1216:    <dt>If the element has no <code title="attr-embed-src"><a href="#attr-embed-src">src</a></code>
                   1217:    attribute set</dt>
                   1218: 
                   1219:    <dd><p>The user agent should find and instantiate an appropriate
                   1220:    <a href="infrastructure.html#plugin">plugin</a> based on the value of the <code title="attr-embed-type"><a href="#attr-embed-type">type</a></code> attribute.</p>
                   1221: 
                   1222:   </dd></dl><p>Whenever an <code><a href="#the-embed-element">embed</a></code> element that was <a href="#concept-embed-active" title="concept-embed-active">potentially active</a> stops being
                   1223:   <a href="#concept-embed-active" title="concept-embed-active">potentially active</a>, any
                   1224:   <a href="infrastructure.html#plugin">plugin</a> that had been instantiated for that element must
                   1225:   be unloaded.</p>
                   1226: 
                   1227:   <p class="note">The <code><a href="#the-embed-element">embed</a></code> element is unaffected by the
                   1228:   CSS 'display' property. The selected plugin is instantiated even if
                   1229:   the element is hidden with a 'display:none' CSS style.</p>
                   1230: 
                   1231:   <p>The <dfn id="concept-embed-type" title="concept-embed-type">type of the content</dfn>
                   1232:   being embedded is defined as follows:</p>
                   1233: 
                   1234:   <ol><li><p>If the element has a <code title="attr-embed-type"><a href="#attr-embed-type">type</a></code> attribute, and that attribute's
                   1235:    value is a type that a <a href="infrastructure.html#plugin">plugin</a> supports, then the value
                   1236:    of the <code title="attr-embed-type"><a href="#attr-embed-type">type</a></code> attribute is the
                   1237:    <a href="#concept-embed-type" title="concept-embed-type">content's type</a>.</p></li>
                   1238: 
                   1239:    <li>
                   1240: 
                   1241:     <!-- if we get to this point we know we can successfully parsed
                   1242:     the URL, since this algorithm is only used after fetching the
                   1243:     resource in the steps above -->
                   1244: 
                   1245:     <p>Otherwise, if the <a href="urls.html#url-path" title="url-path">&lt;path&gt;</a>
                   1246:     component of the <a href="urls.html#url">URL</a> of the specified resource (after
                   1247:     any redirects) matches a pattern that a <a href="infrastructure.html#plugin">plugin</a>
                   1248:     supports, then the <a href="#concept-embed-type" title="concept-embed-type">content's
                   1249:     type</a> is the type that that plugin can handle.</p>
                   1250: 
                   1251:     <p class="example">For example, a plugin might say that it can
                   1252:     handle resources with <a href="urls.html#url-path" title="url-path">&lt;path&gt;</a>
                   1253:     components that end with the four character string "<code title="">.swf</code>".</p>
                   1254: 
                   1255:     <!-- it's sad that we have to do extension sniffing. sigh. -->
                   1256:     <!-- see also <object> which has a similar step -->
                   1257: 
                   1258:    </li>
                   1259: 
                   1260:    <li><p>Otherwise, if the specified resource has <a href="fetching-resources.html#content-type" title="Content-Type">explicit Content-Type metadata</a>, then
                   1261:    that is the <a href="#concept-embed-type" title="concept-embed-type">content's
                   1262:    type</a>.</p></li>
                   1263: 
                   1264:    <li><p>Otherwise, the content has no type and there can be no
                   1265:    appropriate <a href="infrastructure.html#plugin">plugin</a> for it.</p></li>
                   1266: 
                   1267:    <!-- This algorithm is a monument to bad design. Go legacy! -->
                   1268: 
                   1269:   </ol><p>The <code><a href="#the-embed-element">embed</a></code> element has no <a href="content-models.html#fallback-content">fallback
                   1270:   content</a>. If the user agent can't find a suitable plugin, then
                   1271:   the user agent must use a default plugin. (This default could be as
                   1272:   simple as saying "Unsupported Format".)</p>
                   1273: 
                   1274:   <p>Whether the resource is fetched successfully or not (e.g. whether
                   1275:   the response code was a 2xx code <a href="fetching-resources.html#concept-http-equivalent-codes" title="concept-http-equivalent-codes">or equivalent</a>) must be
                   1276:   ignored when determining the resource's type and when handing the
                   1277:   resource to the plugin.</p>
                   1278: 
                   1279:   <p class="note">This allows servers to return data for plugins even
                   1280:   with error responses (e.g. HTTP 500 Internal Server Error codes can
                   1281:   still contain plugin data).</p>
                   1282: 
                   1283:   </div><p>Any namespace-less attribute other than <code title="attr-embed-name"><a href="obsolete.html#attr-embed-name">name</a></code>, <code title="attr-embed-align"><a href="obsolete.html#attr-embed-align">align</a></code>, <code title="attr-embed-hspace"><a href="obsolete.html#attr-embed-hspace">hspace</a></code>, and <code title="attr-embed-vspace"><a href="obsolete.html#attr-embed-vspace">vspace</a></code> <!-- when editing, see also
                   1284:   note below --> may be specified on the <code><a href="#the-embed-element">embed</a></code> element,
                   1285:   so long as its name is <a href="infrastructure.html#xml-compatible">XML-compatible</a> and contains no
                   1286:   characters in the range U+0041 to U+005A (LATIN CAPITAL LETTER A to
                   1287:   LATIN CAPITAL LETTER Z). These attributes are then passed as
                   1288:   parameters to the <a href="infrastructure.html#plugin">plugin</a>.</p><p class="note">All attributes in <a href="dom.html#html-documents">HTML documents</a> get
                   1289:   lowercased automatically, so the restriction on uppercase letters
                   1290:   doesn't affect such documents.</p><p class="note">The four exceptions are to exclude legacy attributes
                   1291:   that have side-effects beyond just sending parameters to the
                   1292:   <a href="infrastructure.html#plugin">plugin</a>.</p><div class="impl">
                   1293: 
                   1294:   <p>The user agent should pass the names and values of all the
                   1295:   attributes of the <code><a href="#the-embed-element">embed</a></code> element that have no namespace
                   1296:   to the <a href="infrastructure.html#plugin">plugin</a> used, when it is instantiated.</p>
                   1297: 
                   1298:   <p>If the <a href="infrastructure.html#plugin">plugin</a> instantiated for the
                   1299:   <code><a href="#the-embed-element">embed</a></code> element supports a scriptable interface, the
                   1300:   <code><a href="#htmlembedelement">HTMLEmbedElement</a></code> object representing the element should
                   1301:   expose that interface while the element is instantiated.</p>
                   1302: 
                   1303:   </div><p>The <code><a href="#the-embed-element">embed</a></code> element supports <a href="the-map-element.html#dimension-attributes">dimension
                   1304:   attributes</a>.</p><div class="impl">
                   1305: 
                   1306:   <p>The IDL attributes <dfn id="dom-embed-src" title="dom-embed-src"><code>src</code></dfn> and <dfn id="dom-embed-type" title="dom-embed-type"><code>type</code></dfn> each must
                   1307:   <a href="common-dom-interfaces.html#reflect">reflect</a> the respective content attributes of the same
                   1308:   name.</p>
                   1309: 
                   1310:   </div><div class="example">
                   1311: 
                   1312:    <p>Here's a way to embed a resource that requires a proprietary
                   1313:    plug-in, like Flash:</p>
                   1314: 
                   1315:    <pre>&lt;embed src="catgame.swf"&gt;</pre>
                   1316: 
                   1317:    <p>If the user does not have the plug-in (for example if the
                   1318:    plug-in vendor doesn't support the user's platform), then the user
                   1319:    will be unable to use the resource.</p>
                   1320: 
                   1321:    <p>To pass the plugin a parameter "quality" with the value "high",
                   1322:    an attribute can be specified:</p>
                   1323: 
                   1324:    <pre>&lt;embed src="catgame.swf" quality="high"&gt;</pre>
                   1325: 
                   1326:    <p>This would be equivalent to the following, when using an
                   1327:    <code><a href="#the-object-element">object</a></code> element instead:</p>
                   1328: 
                   1329:    <pre>&lt;object data="catgame.swf"&gt;
                   1330:  &lt;param name="quality" value="high"&gt;
                   1331: &lt;/object&gt;</pre>
                   1332: 
                   1333:   </div><h4 id="the-object-element"><span class="secno">4.8.4 </span>The <dfn><code>object</code></dfn> element</h4><p class="XXX annotation"><b>Status: </b><i>Last call for comments</i></p><dl class="element"><dt>Categories</dt>
                   1334:    <dd><a href="content-models.html#flow-content">Flow content</a>.</dd>
                   1335:    <dd><a href="content-models.html#phrasing-content">Phrasing content</a>.</dd>
                   1336:    <dd><a href="content-models.html#embedded-content">Embedded content</a>.</dd>
                   1337:    <dd>If the element has a <code title="attr-hyperlink-usemap"><a href="the-map-element.html#attr-hyperlink-usemap">usemap</a></code> attribute: <a href="content-models.html#interactive-content">Interactive content</a>.</dd> <!-- also when showing a plugin or a nested browsing context, but checking that statically is hard...) -->
                   1338:    <dd><a href="forms.html#category-listed" title="category-listed">Listed</a>,  <a href="forms.html#category-submit" title="category-submit">submittable</a>, <a href="forms.html#form-associated-element">form-associated element</a>.</dd>
                   1339:    <dt>Contexts in which this element may be used:</dt>
                   1340:    <dd>Where <a href="content-models.html#embedded-content">embedded content</a> is expected.</dd>
                   1341:    <dt>Content model:</dt>
                   1342:    <dd>Zero or more <code><a href="#the-param-element">param</a></code> elements, then, <a href="content-models.html#transparent">transparent</a>.</dd>
                   1343:    <dt>Content attributes:</dt>
                   1344:    <dd><a href="elements.html#global-attributes">Global attributes</a></dd>
                   1345:    <dd><code title="attr-object-data"><a href="#attr-object-data">data</a></code></dd>
                   1346:    <dd><code title="attr-object-type"><a href="#attr-object-type">type</a></code></dd>
                   1347:    <dd><code title="attr-object-name"><a href="#attr-object-name">name</a></code></dd>
                   1348:    <dd><code title="attr-hyperlink-usemap"><a href="the-map-element.html#attr-hyperlink-usemap">usemap</a></code></dd>
                   1349:    <dd><code title="attr-fae-form"><a href="association-of-controls-and-forms.html#attr-fae-form">form</a></code></dd>
                   1350:    <dd><code title="attr-dim-width"><a href="the-map-element.html#attr-dim-width">width</a></code></dd>
                   1351:    <dd><code title="attr-dim-height"><a href="the-map-element.html#attr-dim-height">height</a></code></dd>
                   1352:    <dt>DOM interface:</dt>
                   1353:    <dd>
                   1354: <pre class="idl">interface <dfn id="htmlobjectelement">HTMLObjectElement</dfn> : <a href="elements.html#htmlelement">HTMLElement</a> {
                   1355:            attribute DOMString <a href="#dom-object-data" title="dom-object-data">data</a>;
                   1356:            attribute DOMString <a href="#dom-object-type" title="dom-object-type">type</a>;
                   1357:            attribute DOMString <a href="#dom-object-name" title="dom-object-name">name</a>;
                   1358:            attribute DOMString <a href="#dom-object-usemap" title="dom-object-useMap">useMap</a>;
                   1359:   readonly attribute <a href="forms.html#htmlformelement">HTMLFormElement</a> <a href="association-of-controls-and-forms.html#dom-fae-form" title="dom-fae-form">form</a>;
                   1360:            attribute DOMString <a href="the-map-element.html#dom-dim-width" title="dom-dim-width">width</a>;
                   1361:            attribute DOMString <a href="the-map-element.html#dom-dim-height" title="dom-dim-height">height</a>;
                   1362:   readonly attribute Document <a href="#dom-object-contentdocument" title="dom-object-contentDocument">contentDocument</a>;
                   1363:   readonly attribute <a href="browsers.html#windowproxy">WindowProxy</a> <a href="#dom-object-contentwindow" title="dom-object-contentWindow">contentWindow</a>;
                   1364: 
                   1365:   readonly attribute boolean <a href="association-of-controls-and-forms.html#dom-cva-willvalidate" title="dom-cva-willValidate">willValidate</a>;
                   1366:   readonly attribute <a href="association-of-controls-and-forms.html#validitystate">ValidityState</a> <a href="association-of-controls-and-forms.html#dom-cva-validity" title="dom-cva-validity">validity</a>;
                   1367:   readonly attribute DOMString <a href="association-of-controls-and-forms.html#dom-cva-validationmessage" title="dom-cva-validationMessage">validationMessage</a>;
                   1368:   boolean <a href="association-of-controls-and-forms.html#dom-cva-checkvalidatity" title="dom-cva-checkValidatity">checkValidity</a>();
                   1369:   void <a href="association-of-controls-and-forms.html#dom-cva-setcustomvalidity" title="dom-cva-setCustomValidity">setCustomValidity</a>(in DOMString error);
                   1370: };</pre>
                   1371:     <div class="impl">
                   1372:     <p>Depending on the type of content instantiated by the
                   1373:     <code><a href="#the-object-element">object</a></code> element, the node also supports other
                   1374:     interfaces.</p>
                   1375:     </div>
                   1376:    </dd>
                   1377:   </dl><p>The <code><a href="#the-object-element">object</a></code> element can represent an external
                   1378:   resource, which, depending on the type of the resource, will either
                   1379:   be treated as an image, as a <a href="browsers.html#nested-browsing-context">nested browsing context</a>,
                   1380:   or as an external resource to be processed by a
                   1381:   <a href="infrastructure.html#plugin">plugin</a>.</p><p>The <dfn id="attr-object-data" title="attr-object-data"><code>data</code></dfn>
                   1382:   attribute, if present, specifies the address of the resource. If
                   1383:   present, the attribute must be a <a href="urls.html#valid-non-empty-url-potentially-surrounded-by-spaces">valid non-empty
                   1384:   URL potentially surrounded by spaces</a>.</p><p>The <dfn id="attr-object-type" title="attr-object-type"><code>type</code></dfn>
                   1385:   attribute, if present, specifies the type of the resource. If
                   1386:   present, the attribute must be a <a href="infrastructure.html#valid-mime-type">valid MIME type</a>.</p><p>At least one of either the <code title="attr-object-data"><a href="#attr-object-data">data</a></code> attribute or the <code title="attr-object-type"><a href="#attr-object-type">type</a></code> attribute must be present.</p><p>The <dfn id="attr-object-name" title="attr-object-name"><code>name</code></dfn>
                   1387:   attribute, if present, must be a <a href="browsers.html#valid-browsing-context-name">valid browsing context
                   1388:   name</a>. The given value is used to name the <a href="browsers.html#nested-browsing-context">nested
                   1389:   browsing context</a>, if applicable.</p><div class="impl">
                   1390: 
                   1391:   <p>When the element is created, when it is popped off the
                   1392:   <a href="parsing.html#stack-of-open-elements">stack of open elements</a> of an <a href="parsing.html#html-parser">HTML parser</a>
                   1393:   or <a href="the-xhtml-syntax.html#xml-parser">XML parser</a>, and subsequently whenever the element is
                   1394:   <a href="infrastructure.html#insert-an-element-into-a-document" title="insert an element into a document">inserted into a
                   1395:   document</a> or <a href="infrastructure.html#remove-an-element-from-a-document" title="remove an element from a
                   1396:   document">removed from a document</a>; and whenever the element's
                   1397:   <code><a href="infrastructure.html#document">Document</a></code> changes whether it is <a href="browsers.html#fully-active">fully
                   1398:   active</a>; and whenever an ancestor <code><a href="#the-object-element">object</a></code> element
                   1399:   changes to or from showing its <a href="content-models.html#fallback-content">fallback content</a>; and
                   1400:   whenever the element's <code title="attr-object-classid"><a href="obsolete.html#attr-object-classid">classid</a></code> attribute is set,
                   1401:   changed, or removed; and, when its <code title="attr-object-classid"><a href="obsolete.html#attr-object-classid">classid</a></code> attribute is not present,
                   1402:   whenever its <code title="attr-object-data"><a href="#attr-object-data">data</a></code> attribute is
                   1403:   set, changed, or removed; and, when neither its <code title="attr-object-classid"><a href="obsolete.html#attr-object-classid">classid</a></code> attribute nor its <code title="attr-object-data"><a href="#attr-object-data">data</a></code> attribute are present, whenever
                   1404:   its <code title="attr-object-type"><a href="#attr-object-type">type</a></code> attribute is set,
                   1405:   changed, or removed: the user agent must <a href="webappapis.html#queue-a-task">queue a task</a>
                   1406:   to run the following steps to (re)determine what the
                   1407:   <code><a href="#the-object-element">object</a></code> element represents. The <a href="webappapis.html#task-source">task source</a>
                   1408:   for this <a href="webappapis.html#concept-task" title="concept-task">task</a> is the <a href="webappapis.html#dom-manipulation-task-source">DOM
                   1409:   manipulation task source</a>.</p> <!-- Changing the base URL
                   1410:   doesn't trigger this. -->
                   1411: 
                   1412:   <ol><li>
                   1413: 
                   1414:     <p>If the user has indicated a preference that this
                   1415:     <code><a href="#the-object-element">object</a></code> element's <a href="content-models.html#fallback-content">fallback content</a> be
                   1416:     shown instead of the element's usual behavior, then jump to the
                   1417:     last step in the overall set of steps (fallback).</p>
                   1418: 
                   1419:     <p class="note">For example, a user could ask for the element's
                   1420:     <a href="content-models.html#fallback-content">fallback content</a> to be shown because that content
                   1421:     uses a format that the user finds more accessible.</p>
                   1422: 
                   1423:    </li>
                   1424: 
                   1425:    <li>
                   1426: 
                   1427:     <p>If the element has an ancestor <a href="video.html#media-element">media element</a>, or
                   1428:     has an ancestor <code><a href="#the-object-element">object</a></code> element that is <em>not</em>
                   1429:     showing its <a href="content-models.html#fallback-content">fallback content</a>, or if the element is
                   1430:     not <a href="infrastructure.html#in-a-document" title="in a document">in a <code>Document</code></a>
                   1431:     with a <a href="browsers.html#browsing-context">browsing context</a>, or if the element's
                   1432:     <code><a href="infrastructure.html#document">Document</a></code> is not <a href="browsers.html#fully-active">fully active</a>, or if the
                   1433:     element is still in the <a href="parsing.html#stack-of-open-elements">stack of open elements</a> of an
                   1434:     <a href="parsing.html#html-parser">HTML parser</a> or <a href="the-xhtml-syntax.html#xml-parser">XML parser</a>, then jump to
                   1435:     the last step in the overall set of steps (fallback).</p>
                   1436: 
                   1437:    </li>
                   1438: 
                   1439:    <li>
                   1440: 
                   1441:     <!-- what if it's not in the document? if that should prevent
                   1442:     plugin instantiation, then here just skip to the last step -->
                   1443: 
                   1444:     <p>If the <code title="attr-object-classid"><a href="obsolete.html#attr-object-classid">classid</a></code>
                   1445:     attribute is present, and has a value that isn't the empty string,
                   1446:     then: if the user agent can find a <a href="infrastructure.html#plugin">plugin</a> suitable
                   1447:     according to the value of the <code title="attr-object-classid"><a href="obsolete.html#attr-object-classid">classid</a></code> attribute, and <a href="#sandboxPluginObject">plugins aren't being sandboxed</a>,
                   1448:     then that <a href="infrastructure.html#plugin">plugin</a> <a href="#object-plugin">should be
                   1449:     used</a>, and the value of the <code title="attr-object-data"><a href="#attr-object-data">data</a></code> attribute, if any, should be
                   1450:     passed to the <a href="infrastructure.html#plugin">plugin</a>. If no suitable
                   1451:     <a href="infrastructure.html#plugin">plugin</a> can be found, or if the <a href="infrastructure.html#plugin">plugin</a>
                   1452:     reports an error, jump to the last step in the overall set of
                   1453:     steps (fallback).</p>
                   1454: 
                   1455:     <!--
                   1456:      case insensitive:
                   1457:       is "clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" -> application/x-shockwave-flash
                   1458:       is "clsid:cfcdaa03-8be4-11cf-b84b-0020afbbccfa" -> audio/x-pn-realaudio-plugin
                   1459:       is "clsid:02bf25d5-8c17-4b23-bc80-d3488abddc6b" -> video/quicktime
                   1460:       is "clsid:166b1bca-3f9c-11cf-8075-444553540000" -> application/x-director
                   1461:       is "clsid:6bf52a52-394a-11d3-b153-00c04f79faa6" -> application/x-mplayer2
                   1462:       starts with "java:"                             -> application/x-java-vm
                   1463:       starts with "clsid:"                            -> application/x-oleobject
                   1464:     -->
                   1465: 
                   1466:    </li>
                   1467: 
                   1468:    <!-- (v2?)
                   1469:    we may have to define magic fallback to <param> if it turns out to
                   1470:    be needed in testing:
                   1471:    <hyatt> apparently your url can come from <param>
                   1472:    <hyatt> not just the data attribute
                   1473:    <hyatt> our code looks for params with "src", "movie", "code" and "url"
                   1474:    <hyatt> and also tries to find the type on a param
                   1475:    <Hixie> oh that's you trying to have hacky activex support
                   1476:    <Hixie> opera does that too
                   1477:    <hyatt> yeah we support activex versions of plugins that are common
                   1478:    <hyatt> like flash and quicktime and realaudio
                   1479:    <Hixie> that would be a step 1b. if no data attribute, then look for a <param> to get you a URL instead.
                   1480:    <Hixie> and if you find one, carry on as if that was your data="".
                   1481:    -->
                   1482: 
                   1483:    <li><p>If the <code title="attr-object-data"><a href="#attr-object-data">data</a></code> attribute
                   1484:    is present and its value is not the empty string, then:</p>
                   1485: 
                   1486:     <ol><li><p>If the <code title="attr-object-type"><a href="#attr-object-type">type</a></code>
                   1487:      attribute is present and its value is not a type that the user
                   1488:      agent supports, and is not a type that the user agent can find a
                   1489:      <a href="infrastructure.html#plugin">plugin</a> for, then the user agent may jump to the last
                   1490:      step in the overall set of steps (fallback) without fetching the
                   1491:      content to examine its real type.</p></li>
                   1492: 
                   1493:      <li><p><a href="urls.html#resolve-a-url" title="resolve a url">Resolve</a> the
                   1494:      <a href="urls.html#url">URL</a> specified by the <code title="attr-object-data"><a href="#attr-object-data">data</a></code> attribute, relative to the
                   1495:      element.</p></li>
                   1496: 
                   1497:      <li><p>If that failed, <a href="webappapis.html#fire-a-simple-event">fire a simple event</a> named
                   1498:      <code title="event-error">error</code> at the element, then jump
                   1499:      to the last step in the overall set of steps (fallback).</p></li>
                   1500: 
                   1501:      <li>
                   1502: 
                   1503:       <p><a href="fetching-resources.html#fetch">Fetch</a> the resulting <a href="urls.html#absolute-url">absolute URL</a>,
                   1504:       from the element's <a href="browsers.html#browsing-context-scope-origin">browsing context scope origin</a> if
                   1505:       it has one<!-- potentially http-origin privacy sensitive
                   1506:       -->.</p>
                   1507: 
                   1508:       <!-- similar text in various places --> <p>Fetching the resource
                   1509:       must <a href="the-end.html#delay-the-load-event">delay the load event</a> of the element's document
                   1510:       until the <a href="webappapis.html#concept-task" title="concept-task">task</a> that is <a href="webappapis.html#queue-a-task" title="queue a task">queued</a> by the <a href="webappapis.html#networking-task-source">networking task
                   1511:       source</a> once the resource has been <a href="fetching-resources.html#fetch" title="fetch">fetched</a> (defined next) has been run.</p>
                   1512: 
                   1513:      </li>
                   1514: 
                   1515:      <li><p>If the resource is not yet available (e.g. because the
                   1516:      resource was not available in the cache, so that loading the
                   1517:      resource required making a request over the network), then jump
                   1518:      to the last step in the overall set of steps (fallback). The
                   1519:      <a href="webappapis.html#concept-task" title="concept-task">task</a> that is <a href="webappapis.html#queue-a-task" title="queue
                   1520:      a task">queued</a> by the <a href="webappapis.html#networking-task-source">networking task source</a>
                   1521:      once the resource is available must restart this algorithm from
                   1522:      this step. Resources can load incrementally; user agents may opt
                   1523:      to consider a resource "available" whenever enough data has been
                   1524:      obtained to begin processing the resource.</p></li>
                   1525: 
                   1526:      <li><p>If the load failed (e.g. there was an HTTP 404 error,
                   1527:      there was a DNS error), <a href="webappapis.html#fire-a-simple-event">fire a simple event</a> named
                   1528:      <code title="event-error">error</code> at the element, then jump
                   1529:      to the last step in the overall set of steps (fallback).</p></li>
                   1530: 
                   1531:      <li id="object-type-detection">
                   1532: 
                   1533:       <p>Determine the <var title="">resource type</var>, as follows:</p>
                   1534: 
                   1535: <!-- Hopefully this step is exactly equivalent to the following:
                   1536: 
                   1537:  START
                   1538:    |
                   1539:    V
                   1540:  Is there a Content-Type and is the UA going to obey it blindly?
                   1541:    |                   |
                   1542:    | YES               | NO
                   1543:    |                   V                                                          YES
                   1544:    |                 Is there a type="" attribute whose value is a plugin type? ============================================-.
                   1545:    |                   |                                                                                                     |
                   1546:    |                   | NO                                                                                                  |
                   1547:    |                   V                        NO                                       YES                                 |
                   1548:    |                 Is there a Content type? ========-> Is there a type="" attribute? ==========> Let TYPE be type=""       |
                   1549:    |                   |                                                           |               attribute value           |
                   1550:    |                   | YES                                                       | NO                    |                 |
                   1551:    V            NO     V                                                           |                       V                 |
                   1552:    +-<============== Is it text/plain or application/octet-stream?                 `==> Let TYPE be  =====>+                 |
                   1553:    |                   |                                     |                          Sniffed type       |                 |
                   1554:    |                   | text/plain                          | octet-stream                                V                 |
                   1555:    |                   V                              YES    V                                          Is TYPE              |
                   1556:    |                 Does the page sniff as binary? ======> Is there a type="" attribute?       application/octet-stream?    |
                   1557:    |                   |                                     |              |                      |                |        |
                   1558:    |                   | NO                                  | YES          | NO                   | YES            | NO     |
                   1559:    |                   |                                     |       YES    V                      V                |        |
                   1560:    |                   |                  application/octet-stream? =====> Extension that is plugin type?           |        |
                   1561:    |                   |                                     |                          |          |                |        |
                   1562:    |                   |                                     | NO                       | NO       | YES            |        |
                   1563:    |                   |                                     V                          |          |                |        |
                   1564:    |                   |                           Type attribute is XML or     YES     V          |                |        |
                   1565:    |                   |                           doesn't start with image/* ======> FALLBACK     |                |        |
                   1566:    |                   |                           and is not a plugin type?                       |                |        |
                   1567:    |                   |                                          |                                |                |        |
                   1568:    |                   |                                          | NO                             |                |        V
                   1569:    V                   V                                          V                                V                V       Use
                   1570:   Use                 Use                                        Use it (will be                  Use              Use      type=""
                   1571:   Content-Type        text/plain                                 bitmap or plugin)                extension        TYPE     attribute
                   1572:    |                   |                                          |                                |                |        |
                   1573:    |                   V                                          V                                V                V        |
                   1574:    `================->-+========================================>-+==============>-+-<============-+-<==============+-<======'
                   1575:                                                                                    |
                   1576:                                                                                    V
                   1577:                                                                   Continue following rules in the spec, which might
                   1578:                                                                   result in a plugin, a browsing context, an image,
                   1579:                                                                   or using fallback, depending on the UA and the type.
                   1580: 
                   1581: 
                   1582:    "Extension that is plugin type?" means "Is there an extension that matches one that a plugin supports?".
                   1583:    Plugins are not allowed to register text/plain or application/octet-stream.
                   1584: 
                   1585: -->
                   1586: 
                   1587:       <ol><li>
                   1588: 
                   1589:         <p>Let the <var title="">resource type</var> be unknown.</p>
                   1590: 
                   1591:        </li>
                   1592: 
                   1593:        <li>
                   1594: 
                   1595:         <!-- by request: http://www.w3.org/Bugs/Public/show_bug.cgi?id=8479 -->
                   1596: 
                   1597:         <p>If the user agent is configured to strictly obey
                   1598:         Content-Type headers for this resource, and the resource has
                   1599:         <a href="fetching-resources.html#content-type" title="Content-Type">associated Content-Type
                   1600:         metadata</a>, then let the <var title="">resource
                   1601:         type</var> be the type specified in <a href="fetching-resources.html#content-type" title="Content-Type">the resource's Content-Type
                   1602:         metadata</a>, and jump to the step below labeled
                   1603:         <i>handler</i>.</p>
                   1604: 
                   1605:        </li>
                   1606: 
                   1607:        <li>
                   1608: 
                   1609:         <p>If there is a <code title="attr-object-type"><a href="#attr-object-type">type</a></code>
                   1610:         attribute present on the <code><a href="#the-object-element">object</a></code> element, and that
                   1611:         attribute's value is not a type that the user agent supports,
                   1612:         but it <em>is</em> a type that a <a href="infrastructure.html#plugin">plugin</a> supports,
                   1613:         then let the <var title="">resource type</var> be the type
                   1614:         specified in that <code title="attr-object-type"><a href="#attr-object-type">type</a></code>
                   1615:         attribute, and jump to the step below labeled
                   1616:         <i>handler</i>.</p>
                   1617: 
                   1618:        </li>
                   1619: 
                   1620:        <li>
                   1621: 
                   1622:         <p>Run the approprate set of steps from the following
                   1623:         list:</p>
                   1624: 
                   1625:         <dl class="switch"><dt>The resource has <a href="fetching-resources.html#content-type" title="Content-Type">associated
                   1626:          Content-Type metadata</a></dt>
                   1627: 
                   1628:          <dd>
                   1629: 
                   1630:           <ol><li>
                   1631: 
                   1632:             <p>Let <var title="">binary</var> be false.</p>
                   1633: 
                   1634:            </li>
                   1635: 
                   1636:            <li>
                   1637: 
                   1638:             <p>If the type specified in <a href="fetching-resources.html#content-type" title="Content-Type">the
                   1639:             resource's Content-Type metadata</a> is
                   1640:             "<code>text/plain</code>", and the result of applying the
                   1641:             <a href="fetching-resources.html#content-type-sniffing:-text-or-binary" title="Content-Type sniffing: text or binary">rules
                   1642:             for distingushing if a resource is text or binary</a>
                   1643:             to the resource is that the resource is not
                   1644:             <code>text/plain</code>, then set <var title="">binary</var> to true.</p>
                   1645: 
                   1646:            </li>
                   1647: 
                   1648:            <li>
                   1649: 
                   1650:             <p>If the type specified in <a href="fetching-resources.html#content-type" title="Content-Type">the
                   1651:             resource's Content-Type metadata</a> is
                   1652:             "<code>application/octet-stream</code>", then set <var title="">binary</var> to true.</p>
                   1653: 
                   1654:            </li>
                   1655: 
                   1656:            <li>
                   1657: 
                   1658:             <p>If <var title="">binary</var> is false, then let the
                   1659:             <var title="">resource type</var> be the type specified in
                   1660:             <a href="fetching-resources.html#content-type" title="Content-Type">the resource's Content-Type
                   1661:             metadata</a>, and jump to the step below labeled
                   1662:             <i>handler</i>.</p>
                   1663: 
                   1664:            </li>
                   1665: 
                   1666:            <li>
                   1667: 
                   1668:             <p>If there is a <code title="attr-object-type"><a href="#attr-object-type">type</a></code> attribute present on
                   1669:             the <code><a href="#the-object-element">object</a></code> element, and its value is not
                   1670:             <code>application/octet-stream</code>, then run the
                   1671:             following steps:</p>
                   1672: 
                   1673:             <ol><li>
                   1674: 
                   1675:               <p>If the attribute's value is a type that a <a href="infrastructure.html#plugin">plugin</a> supports, or
                   1676:               the attribute's value is a type that starts with "<code>image/</code>" that is not also an <a href="infrastructure.html#xml-mime-type">XML MIME type</a>,
                   1677:               then let the <var title="">resource type</var> be the type specified in that <code title="attr-object-type"><a href="#attr-object-type">type</a></code> attribute.</p>
                   1678: 
                   1679:              </li>
                   1680: 
                   1681:              <li>
                   1682: 
                   1683:               <p>Jump to the step below labeled <i>handler</i>.</p>
                   1684: 
                   1685:              </li>
                   1686: 
                   1687:             </ol></li>
                   1688: 
                   1689:           </ol></dd>
                   1690: 
                   1691:          <dt>The resource does not have <a href="fetching-resources.html#content-type" title="Content-Type">associated Content-Type
                   1692:          metadata</a></dt>
                   1693: 
                   1694:          <dd>
                   1695: 
                   1696:           <ol><li>
                   1697: 
                   1698:             <p>If there is a <code title="attr-object-type"><a href="#attr-object-type">type</a></code> attribute present on
                   1699:             the <code><a href="#the-object-element">object</a></code> element, then let the <var title="">tentative type</var> be the type specified in that
                   1700:             <code title="attr-object-type"><a href="#attr-object-type">type</a></code> attribute.</p>
                   1701: 
                   1702:             <p>Otherwise, let <var title="">tentative type</var> be the
                   1703:             <a href="fetching-resources.html#content-type-sniffing-0" title="content-type sniffing">sniffed type of the
                   1704:             resource</a>.</p>
                   1705: 
                   1706:            </li>
                   1707: 
                   1708:            <li>
                   1709: 
                   1710:             <p>If <var title="">tentative type</var> is <em>not</em>
                   1711:             <code>application/octet-stream</code>, then let <var title="">resource type</var> be <var title="">tentative
                   1712:             type</var> and jump to the step below labeled
                   1713:             <i>handler</i>.</p>
                   1714: 
                   1715:            </li>
                   1716: 
                   1717:           </ol></dd>
                   1718: 
                   1719:         </dl></li>
                   1720: 
                   1721:        <li>
                   1722: 
                   1723:         <!-- if we get to this point we know we can successfully
                   1724:         parsed the URL, since this algorithm is only used after
                   1725:         fetching the resource in the steps above -->
                   1726: 
                   1727:         <p>If the <a href="urls.html#url-path" title="url-path">&lt;path&gt;</a> component
                   1728:         of the <a href="urls.html#url">URL</a> of the specified resource (after any
                   1729:         redirects) matches a pattern that a <a href="infrastructure.html#plugin">plugin</a>
                   1730:         supports, then let <var title="">resource type</var> be the
                   1731:         type that that plugin can handle.</p>
                   1732: 
                   1733:         <p class="example">For example, a plugin might say that it can
                   1734:         handle resources with <a href="urls.html#url-path" title="url-path">&lt;path&gt;</a> components that end with
                   1735:         the four character string "<code title="">.swf</code>".</p>
                   1736: 
                   1737:         <!-- it's sad that we have to do extension sniffing. sigh. -->
                   1738:         <!-- see also <embed> which has a similar step -->
                   1739: 
                   1740:        </li>
                   1741: 
                   1742:       </ol><p class="note">It is possible for this step to finish with <var title="">resource type</var> still being unknown, or for one of
                   1743:       the substeps above to jump straight to the next step. In both
                   1744:       cases, the next step will trigger fallback.</p>
                   1745: 
                   1746:      </li>
                   1747: 
                   1748:      <li><p><i>Handler</i>: Handle the content as given by the first
                   1749:      of the following cases that matches:</p>
                   1750: 
                   1751:       <dl class="switch"><dt>If the <var title="">resource type</var> is not a type that
                   1752:        the user agent supports, but it <em>is</em> a type that a
                   1753:        <a href="infrastructure.html#plugin">plugin</a> supports</dt>
                   1754: 
                   1755:        <dd>
                   1756: 
                   1757:         <p>If <a href="#sandboxPluginObject">plugins are being
                   1758:         sandboxed</a>, jump to the last step in the overall set of
                   1759:         steps (fallback).</p>
                   1760: 
                   1761:         <p>Otherwise, the user agent should <a href="#object-plugin">use the plugin that supports <var title="">resource type</var></a> and pass the content of the
                   1762:         resource to that <a href="infrastructure.html#plugin">plugin</a>. If the
                   1763:         <a href="infrastructure.html#plugin">plugin</a> reports an error, then jump to the last
                   1764:         step in the overall set of steps (fallback).</p>
                   1765: 
                   1766:        </dd>
                   1767: 
                   1768: 
                   1769:        <dt>If the <var title="">resource type</var> is an <a href="infrastructure.html#xml-mime-type">XML MIME
                   1770:        type</a>, or
                   1771:        <!-- (redundant with the next one) if the <var title="">resource type</var> is HTML, or -->
                   1772:        if the <var title="">resource type</var> does not start with
                   1773:        "<code>image/</code>"</dt>
                   1774: 
                   1775:        <dd>
                   1776: 
                   1777:         <p>The <code><a href="#the-object-element">object</a></code> element must be associated with a
                   1778:         newly created <a href="browsers.html#nested-browsing-context">nested browsing context</a>, if it does
                   1779:         not already have one.</p>
                   1780: 
                   1781:         <p>If the <a href="urls.html#url">URL</a> of the given resource is not
                   1782:         <code><a href="fetching-resources.html#about:blank">about:blank</a></code>, the element's <a href="browsers.html#nested-browsing-context">nested browsing
                   1783:         context</a> must then be <a href="history.html#navigate" title="navigate">navigated</a> to that resource, with
                   1784:         <a href="history.html#replacement-enabled">replacement enabled</a>, and with the
                   1785:         <code><a href="#the-object-element">object</a></code> element's document's <a href="browsers.html#browsing-context">browsing
                   1786:         context</a> as the <a href="history.html#source-browsing-context">source browsing
                   1787:         context</a>. (The <code title="attr-object-data"><a href="#attr-object-data">data</a></code> attribute of the
                   1788:         <code><a href="#the-object-element">object</a></code> element doesn't get updated if the
                   1789:         browsing context gets further navigated to other
                   1790:         locations.)</p>
                   1791: 
                   1792:         <p>If the <a href="urls.html#url">URL</a> of the given resource <em>is</em>
                   1793:         <code><a href="fetching-resources.html#about:blank">about:blank</a></code>, then, instead, the user agent must
                   1794:         <a href="webappapis.html#queue-a-task">queue a task</a> to <a href="webappapis.html#fire-a-simple-event">fire a simple event</a>
                   1795:         named <code title="event-load">load</code> at the
                   1796:         <code><a href="#the-object-element">object</a></code> element.</p>
                   1797: 
                   1798:         <p>The <code><a href="#the-object-element">object</a></code> element <a href="rendering.html#represents">represents</a> the
                   1799:         <a href="browsers.html#nested-browsing-context">nested browsing context</a>.</p>
                   1800: 
                   1801:         <p>If the <code title="attr-object-name"><a href="#attr-object-name">name</a></code> attribute
                   1802:         is present, the <a href="browsers.html#browsing-context-name">browsing context name</a> must be set
                   1803:         to the value of this attribute; otherwise, the <a href="browsers.html#browsing-context-name">browsing
                   1804:         context name</a> must be set to the empty string.</p>
                   1805: 
                   1806:         <p class="note">It's possible that the <a href="history.html#navigate" title="navigate">navigation</a> of the <a href="browsers.html#browsing-context">browsing
                   1807:         context</a> will actually obtain the resource from a
                   1808:         different <a href="offline.html#application-cache">application cache</a>. Even if the resource
                   1809:         is then found to have a different type, it is still used as
                   1810:         part of a <a href="browsers.html#nested-browsing-context">nested browsing context</a>; this algorithm
                   1811:         doesn't restart with the new resource.</p>
                   1812: 
                   1813:         <!-- note that malformed XML files don't cause fallback -->
                   1814: 
                   1815:        </dd>
                   1816: 
                   1817: 
                   1818:        <dt>If the <var title="">resource type</var> starts with
                   1819:        "<code>image/</code>", and support for images has not been
                   1820:        disabled</dt>
                   1821: 
                   1822:        <dd>
                   1823: 
                   1824:         <p>Apply the <a href="fetching-resources.html#content-type-sniffing:-image" title="content-type sniffing: image">image
                   1825:         sniffing</a> rules to determine the type of the image.</p>
                   1826: 
                   1827:         <p>The <code><a href="#the-object-element">object</a></code> element <a href="rendering.html#represents">represents</a> the
                   1828:         specified image. The image is not a <a href="browsers.html#nested-browsing-context">nested browsing
                   1829:         context</a>.</p>
                   1830: 
                   1831:         <p>If the image cannot be rendered, e.g. because it is
                   1832:         malformed or in an unsupported format, jump to the last step
                   1833:         in the overall set of steps (fallback).</p>
                   1834: 
                   1835:        </dd>
                   1836: 
                   1837: 
                   1838:        <dt>Otherwise</dt>
                   1839: 
                   1840:        <dd>
                   1841: 
                   1842:         <p>The given <var title="">resource type</var> is not
                   1843:         supported. Jump to the last step in the overall set of steps
                   1844:         (fallback).</p>
                   1845: 
                   1846:         <p class="note">If the previous step ended with the <var title="">resource type</var> being unknown, this is the case
                   1847:         that is triggered.</p>
                   1848: 
                   1849:        </dd>
                   1850: 
                   1851:       </dl></li>
                   1852: 
                   1853:      <li><p>The element's contents are not part of what the
                   1854:      <code><a href="#the-object-element">object</a></code> element represents.</p>
                   1855: 
                   1856:      </li><li>
                   1857: 
                   1858:       <p>Once the resource is completely loaded, <a href="webappapis.html#queue-a-task">queue a
                   1859:       task</a> to <a href="webappapis.html#fire-a-simple-event">fire a simple event</a> named <code title="event-load">load</code> at the element.</p>
                   1860: 
                   1861:       <p>The <a href="webappapis.html#task-source">task source</a> for this task<!--tasks mentioned
                   1862:       in this section--> is the <a href="webappapis.html#dom-manipulation-task-source">DOM manipulation task
                   1863:       source</a>.</p>
                   1864: 
                   1865:      </li>
                   1866: 
                   1867:     </ol></li>
                   1868: 
                   1869:    <li><p>If the <code title="attr-object-data"><a href="#attr-object-data">data</a></code> attribute
                   1870:    is absent but the <code title="attr-object-type"><a href="#attr-object-type">type</a></code>
                   1871:    attribute is present, <a href="#sandboxPluginObject">plugins aren't
                   1872:    being sandboxed</a>, and the user agent can find a
                   1873:    <a href="infrastructure.html#plugin">plugin</a> suitable according to the value of the <code title="attr-object-type"><a href="#attr-object-type">type</a></code> attribute, then that
                   1874:    <a href="infrastructure.html#plugin">plugin</a> <a href="#object-plugin">should be used</a>. If
                   1875:    no suitable <a href="infrastructure.html#plugin">plugin</a> can be found, or if the
                   1876:    <a href="infrastructure.html#plugin">plugin</a> reports an error, jump to the next step
                   1877:    (fallback).</p></li>
                   1878: 
                   1879:    <li><p>(Fallback.) The <code><a href="#the-object-element">object</a></code> element
                   1880:    <a href="rendering.html#represents">represents</a> the element's children, ignoring any
                   1881:    leading <code><a href="#the-param-element">param</a></code> element children. This is the element's
                   1882:    <a href="content-models.html#fallback-content">fallback content</a>. If the element has an instantiated
                   1883:    <a href="infrastructure.html#plugin">plugin</a>, then unload it.</p></li>
                   1884: 
                   1885:   </ol><p id="object-plugin">When the algorithm above instantiates a
                   1886:   <a href="infrastructure.html#plugin">plugin</a>, the user agent should pass to the
                   1887:   <a href="infrastructure.html#plugin">plugin</a> used the names and values of all the attributes
                   1888:   on the element, in the order they were added to the element, with
                   1889:   the attributes added by the parser being ordered in source order,
                   1890:   followed by a parameter named "PARAM" whose value is null,
                   1891:   followed by all the names and values of <a href="#concept-param-parameter" title="concept-param-parameter">parameters</a> given by
                   1892:   <code><a href="#the-param-element">param</a></code> elements that are children of the
                   1893:   <code><a href="#the-object-element">object</a></code> element, in <a href="infrastructure.html#tree-order">tree order</a>. If the
                   1894:   <a href="infrastructure.html#plugin">plugin</a> supports a scriptable interface, the
                   1895:   <code><a href="#htmlobjectelement">HTMLObjectElement</a></code> object representing the element
                   1896:   should expose that interface. The <code><a href="#the-object-element">object</a></code> element
                   1897:   <a href="rendering.html#represents">represents</a> the <a href="infrastructure.html#plugin">plugin</a>. The
                   1898:   <a href="infrastructure.html#plugin">plugin</a> is not a nested <a href="browsers.html#browsing-context">browsing
                   1899:   context</a>.</p>
                   1900: 
                   1901:   <p id="sandboxPluginObject">If either:</p>
                   1902: 
                   1903:   <ul><li>the <a href="#sandboxed-plugins-browsing-context-flag">sandboxed plugins browsing context flag</a> was
                   1904:    set on the <code><a href="#the-object-element">object</a></code> element's <code><a href="infrastructure.html#document">Document</a></code>'s
                   1905:    <a href="browsers.html#browsing-context">browsing context</a> when the <code><a href="infrastructure.html#document">Document</a></code> was
                   1906:    created, or</li>
                   1907: 
                   1908:    <li>the <code><a href="#the-object-element">object</a></code> element's <code><a href="infrastructure.html#document">Document</a></code> was
                   1909:    parsed from a resource whose <a href="fetching-resources.html#content-type-sniffing-0" title="Content-Type
                   1910:    sniffing">sniffed type</a> as determined during <a href="history.html#navigate" title="navigate">navigation</a> is
                   1911:    <code><a href="iana.html#text-html-sandboxed">text/html-sandboxed</a></code></li>
                   1912: 
                   1913:   </ul><p>...then the steps above must always act as if they had failed to
                   1914:   find a <a href="infrastructure.html#plugin">plugin</a>, even if one would otherwise have been
                   1915:   used.</p>
                   1916: 
                   1917:   <p class="note">The above algorithm is independent of CSS properties
                   1918:   (including 'display', 'overflow', and 'visibility'). For example, it
                   1919:   runs even if the element is hidden with a 'display:none' CSS style,
                   1920:   and does not run <em>again</em> if the element's visibility
                   1921:   changes.</p>
                   1922: 
                   1923:   <p>Due to the algorithm above, the contents of <code><a href="#the-object-element">object</a></code>
                   1924:   elements act as <a href="content-models.html#fallback-content">fallback content</a>, used only when
                   1925:   referenced resources can't be shown (e.g. because it returned a 404
                   1926:   error). This allows multiple <code><a href="#the-object-element">object</a></code> elements to be
                   1927:   nested inside each other, targeting multiple user agents with
                   1928:   different capabilities, with the user agent picking the first one it
                   1929:   supports.</p>
                   1930: 
                   1931:   <p>Whenever the <code title="attr-object-name"><a href="#attr-object-name">name</a></code> attribute
                   1932:   is set, if the <code><a href="#the-object-element">object</a></code> element has a nested
                   1933:   <a href="browsers.html#browsing-context">browsing context</a>, its <a href="browsers.html#browsing-context-name" title="browsing context
                   1934:   name">name</a> must be changed to the new value. If the attribute
                   1935:   is removed, if the <code><a href="#the-object-element">object</a></code> element has a <a href="browsers.html#browsing-context">browsing
                   1936:   context</a>, the <a href="browsers.html#browsing-context-name">browsing context name</a> must be set
                   1937:   to the empty string.</p>
                   1938: 
                   1939:   </div><p>The <code title="attr-hyperlink-usemap"><a href="the-map-element.html#attr-hyperlink-usemap">usemap</a></code> attribute,
                   1940:   if present while the <code><a href="#the-object-element">object</a></code> element represents an
                   1941:   image, can indicate that the object has an associated <a href="the-map-element.html#image-map">image
                   1942:   map</a>. <span class="impl">The attribute must be ignored if the
                   1943:   <code><a href="#the-object-element">object</a></code> element doesn't represent an image.</span></p><p>The <code title="attr-fae-form"><a href="association-of-controls-and-forms.html#attr-fae-form">form</a></code> attribute is used to
                   1944:   explicitly associate the <code><a href="#the-object-element">object</a></code> element with its
                   1945:   <a href="association-of-controls-and-forms.html#form-owner">form owner</a>.</p><div class="impl">
                   1946: 
                   1947:   <p><strong>Constraint validation</strong>: <code><a href="#the-object-element">object</a></code>
                   1948:   elements are always <a href="association-of-controls-and-forms.html#barred-from-constraint-validation">barred from constraint
                   1949:   validation</a>.</p>
                   1950: 
                   1951:   </div><p>The <code><a href="#the-object-element">object</a></code> element supports <a href="the-map-element.html#dimension-attributes">dimension
                   1952:   attributes</a>.</p><div class="impl">
                   1953: 
                   1954:   <p>The IDL attributes <dfn id="dom-object-data" title="dom-object-data"><code>data</code></dfn>, <dfn id="dom-object-type" title="dom-object-type"><code>type</code></dfn>, <dfn id="dom-object-name" title="dom-object-name"><code>name</code></dfn>, and <dfn id="dom-object-usemap" title="dom-object-useMap"><code>useMap</code></dfn> each must
                   1955:   <a href="common-dom-interfaces.html#reflect">reflect</a> the respective content attributes of the same
                   1956:   name.</p>
                   1957: 
                   1958:   <p>The <dfn id="dom-object-contentdocument" title="dom-object-contentDocument"><code>contentDocument</code></dfn>
                   1959:   IDL attribute must return the <code><a href="infrastructure.html#document">Document</a></code> object of the
                   1960:   <a href="browsers.html#active-document">active document</a> of the <code><a href="#the-object-element">object</a></code> element's
                   1961:   <a href="browsers.html#nested-browsing-context">nested browsing context</a>, if it has one; otherwise, it
                   1962:   must return null.</p>
                   1963: 
                   1964:   <p>The <dfn id="dom-object-contentwindow" title="dom-object-contentWindow"><code>contentWindow</code></dfn>
                   1965:   IDL attribute must return the <code><a href="browsers.html#windowproxy">WindowProxy</a></code> object of the
                   1966:   <code><a href="#the-object-element">object</a></code> element's <a href="browsers.html#nested-browsing-context">nested browsing context</a>,
                   1967:   if it has one; otherwise, it must return null.</p>
                   1968: 
                   1969:   <p>The <code title="dom-cva-willValidate"><a href="association-of-controls-and-forms.html#dom-cva-willvalidate">willValidate</a></code>, <code title="dom-cva-validity"><a href="association-of-controls-and-forms.html#dom-cva-validity">validity</a></code>, and <code title="dom-cva-validationMessage"><a href="association-of-controls-and-forms.html#dom-cva-validationmessage">validationMessage</a></code>
                   1970:   attributes, and the <code title="dom-cva-checkValidatity"><a href="association-of-controls-and-forms.html#dom-cva-checkvalidatity">checkValidity()</a></code> and <code title="dom-cva-setCustomValidity"><a href="association-of-controls-and-forms.html#dom-cva-setcustomvalidity">setCustomValidity()</a></code>
                   1971:   methods, are part of the <a href="association-of-controls-and-forms.html#the-constraint-validation-api">constraint validation API</a>. The
                   1972:   <code title="dom-fae-form"><a href="association-of-controls-and-forms.html#dom-fae-form">form</a></code> IDL attribute is part of the
                   1973:   element's forms API.</p>
                   1974: 
                   1975:   </div><div class="example">
                   1976: 
                   1977:    <p>In the following example, a Java applet is embedded in a page
                   1978:    using the <code><a href="#the-object-element">object</a></code> element. (Generally speaking, it is
                   1979:    better to avoid using applets like these and instead use native
                   1980:    JavaScript and HTML to provide the functionality, since that way
                   1981:    the application will work on all Web browsers without requiring a
                   1982:    third-party plugin. Many devices, especially embedded devices, do
                   1983:    not support third-party technologies like Java.)</p>
                   1984: 
                   1985:    <pre>&lt;figure&gt;
                   1986:  &lt;object type="application/x-java-applet"&gt;
                   1987:   &lt;param name="code" value="MyJavaClass"&gt;
                   1988:   &lt;p&gt;You do not have Java available, or it is disabled.&lt;/p&gt;
                   1989:  &lt;/object&gt;
                   1990:  &lt;figcaption&gt;My Java Clock&lt;/figcaption&gt;
                   1991: &lt;/figure&gt;</pre>
                   1992: 
                   1993:   </div><div class="example">
                   1994: 
                   1995:    <p>In this example, an HTML page is embedded in another using the
                   1996:    <code><a href="#the-object-element">object</a></code> element.</p>
                   1997: 
                   1998:    <pre>&lt;figure&gt;
                   1999:  &lt;object data="clock.html"&gt;&lt;/object&gt;
                   2000:  &lt;figcaption&gt;My HTML Clock&lt;/figcaption&gt;
                   2001: &lt;/figure&gt;</pre>
                   2002: 
                   2003:   </div><div class="example">
                   2004: 
                   2005:    <p>The following example shows how a plugin can be used in HTML (in
                   2006:    this case the Flash plugin, to show a video file). Fallback is
                   2007:    provided for users who do not have Flash enabled, in this case
                   2008:    using the <code><a href="video.html#video">video</a></code> element to show the video for those
                   2009:    using user agents that support <code><a href="video.html#video">video</a></code>, and finally
                   2010:    providing a link to the video for those who have neither Flash nor
                   2011:    a <code><a href="video.html#video">video</a></code>-capable browser.</p>
                   2012: 
                   2013:    <pre>&lt;p&gt;Look at my video:
                   2014:  &lt;object type="application/x-shockwave-flash"&gt;
                   2015:   &lt;param name=movie value="http://video.example.com/library/watch.swf"&gt;
                   2016:   &lt;param name=allowfullscreen value=true&gt;
                   2017:   &lt;param name=flashvars value="http://video.example.com/vids/315981"&gt;
                   2018:   &lt;video controls src="http://video.example.com/vids/315981"&gt;
                   2019:    &lt;a href="http://video.example.com/vids/315981"&gt;View video&lt;/a&gt;.
                   2020:   &lt;/video&gt;
                   2021:  &lt;/object&gt;
                   2022: &lt;/p&gt;</pre>
                   2023: 
                   2024:   </div><h4 id="the-param-element"><span class="secno">4.8.5 </span>The <dfn><code>param</code></dfn> element</h4><p class="XXX annotation"><b>Status: </b><i>Last call for comments</i></p><dl class="element"><dt>Categories</dt>
                   2025:    <dd>None.</dd>
                   2026:    <dt>Contexts in which this element may be used:</dt>
                   2027:    <dd>As a child of an <code><a href="#the-object-element">object</a></code> element, before any <a href="content-models.html#flow-content">flow content</a>.</dd>
                   2028:    <dt>Content model:</dt>
                   2029:    <dd>Empty.</dd>
                   2030:    <dt>Content attributes:</dt>
                   2031:    <dd><a href="elements.html#global-attributes">Global attributes</a></dd>
                   2032:    <dd><code title="attr-param-name"><a href="#attr-param-name">name</a></code></dd>
                   2033:    <dd><code title="attr-param-value"><a href="#attr-param-value">value</a></code></dd>
                   2034:    <dt>DOM interface:</dt>
                   2035:    <dd>
                   2036: <pre class="idl">interface <dfn id="htmlparamelement">HTMLParamElement</dfn> : <a href="elements.html#htmlelement">HTMLElement</a> {
                   2037:            attribute DOMString <a href="#dom-param-name" title="dom-param-name">name</a>;
                   2038:            attribute DOMString <a href="#dom-param-value" title="dom-param-value">value</a>;
                   2039: };</pre>
                   2040:    </dd>
                   2041:   </dl><p>The <code><a href="#the-param-element">param</a></code> element defines parameters for plugins
                   2042:   invoked by <code><a href="#the-object-element">object</a></code> elements. It does not <a href="rendering.html#represents" title="represents">represent</a> anything on its own.</p><p>The <dfn id="attr-param-name" title="attr-param-name"><code>name</code></dfn>
                   2043:   attribute gives the name of the parameter.</p><p>The <dfn id="attr-param-value" title="attr-param-value"><code>value</code></dfn>
                   2044:   attribute gives the value of the parameter.</p><p>Both attributes must be present. They may have any value.</p><div class="impl">
                   2045: 
                   2046:   <p>If both attributes are present, and if the parent element of the
                   2047:   <code><a href="#the-param-element">param</a></code> is an <code><a href="#the-object-element">object</a></code> element, then the
                   2048:   element defines a <dfn id="concept-param-parameter" title="concept-param-parameter">parameter</dfn> with the given
                   2049:   name/value pair.</p>
                   2050: 
                   2051:   <p>The IDL attributes <dfn id="dom-param-name" title="dom-param-name"><code>name</code></dfn> and <dfn id="dom-param-value" title="dom-param-value"><code>value</code></dfn> must both
                   2052:   <a href="common-dom-interfaces.html#reflect">reflect</a> the respective content attributes of the same
                   2053:   name.</p>
                   2054: 
                   2055:   </div><div class="example">
                   2056: 
                   2057:    <p>The following example shows how the <code><a href="#the-param-element">param</a></code> element
                   2058:    can be used to pass a parameter to a plugin, in this case the O3D
                   2059:    plugin.</p>
                   2060: 
                   2061:    <pre>&lt;!DOCTYPE HTML&gt;
                   2062: &lt;html lang="en"&gt;
1.6       mike     2063:   &lt;head&gt;
                   2064:    &lt;title&gt;O3D Utah Teapot&lt;/title&gt;
                   2065:   &lt;/head&gt;
                   2066:   &lt;body&gt;
                   2067:    &lt;p&gt;
                   2068:     &lt;object type="application/vnd.o3d.auto"&gt;
                   2069:      <strong>&lt;param name="o3d_features" value="FloatingPointTextures"&gt;</strong>
                   2070:      &lt;img src="o3d-teapot.png"
                   2071:           title="3D Utah Teapot illustration rendered using O3D."
                   2072:           alt="When O3D renders the Utah Teapot, it appears as a squat
                   2073:           teapot with a shiny metallic finish on which the
                   2074:           surroundings are reflected, with a faint shadow caused by
                   2075:           the lighting."&gt;
                   2076:      &lt;p&gt;To see the teapot actually rendered by O3D on your
                   2077:      computer, please download and install the &lt;a
                   2078:      href="http://code.google.com/apis/o3d/docs/gettingstarted.html#install"&gt;O3D plugin&lt;/a&gt;.&lt;/p&gt;
                   2079:     &lt;/object&gt;
                   2080:     &lt;script src="o3d-teapot.js"&gt;&lt;/script&gt;
                   2081:    &lt;/p&gt;
                   2082:   &lt;/body&gt;
1.1       mike     2083: &lt;/html&gt;</pre>
                   2084: 
                   2085:   </div></body></html>

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