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Check if a Number is NaN in JavaScript
NaN is a JavaScript property, which is Not-a-Number value. This shows it is not a legal number. Here’s the syntax −
Syntax
Number.NaN
To find out whether a number is NaN, use the Number.isNaN() or isNan() method. Here’s an example to check −
Example
<!DOCTYPE html>
<html>
<body>
<button onclick="display()">Check</button>
<p id="test"></p>
<script>
function display() {
var a = "";
a = a + isNaN(434) + ": 434<br>";
a = a + isNaN(-23.1) + ": -23.1<br>";
a = a + isNaN('Hello') + ": 'Hello'<br>";
a = a + isNaN(NaN) + ": NaN<br>";
a = a + isNaN('') + ": ''<br>";
a = a + isNaN(0) + ": 0<br>";
a = a + isNaN(false) + ": false<br>";
document.getElementById("test").innerHTML = a;
}
</script>
</body>
</html>
Updated on: 2020-06-17T06:30:40+05:30
229 Views
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