HTML DOM Window atob( ) Method

Last Updated : 15 Jun, 2023

The Window atob() method is used for decoding a base-64 encoded string. It is used to decode a string of data which has been encoded using the btoa() method. It returns a string which represents the decoded string.

Syntax :

window.atob(EncodedString)

Parameters Used :

EncodedString : It is a mandatory parameter which specifies the encoded string.

Below program illustrates the Window atob() Method :

Decoding a string encoded using the btoa() method.

html

<!DOCTYPE html>
<html>

<head>
    <title>
      Window atob() Method in HTML
    </title>
    <style>
        h1 {
            color: green;
        }
        
        h2 {
            font-family: Impact;
        }
        
        body {
            text-align: center;
        }
    </style>
</head>

<body>

    <h1>GeeksforGeeks</h1>
    <h2>Window atob() Method</h2>

    <p>
      For decoding a base-64 encoded string,
      double click the "Decode Message" button:
    </p>

    <button ondblclick="decode()">
      Decode Message
    </button>

    <p id="myDecoding"></p>

    <script>
        function decode() {
            var original = "GeeksforGeeks";
            var encoded = window.btoa(original);
            var decoded = window.atob(encoded);

            var output = "Encoded String : " 
            + encoded + "<br>" + "Decoded String : "
            + decoded;
            document.getElementById("myDecoding").innerHTML =
              output;
        }
    </script>

</body>

</html>