Tryit Editor v2.9

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<!DOCTYPE html>
<html>
<body>

<p>The Number.isNaN() function returns true if the value is Number.NaN (Not-a-Number), and false if not.</p>

<p>Click the button to check whether a number is NaN.</p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<p><strong>Note:</strong> The Number.isNaN() function is not supported in IE 11 (and earlier versions).</p>

<script>
function myFunction() {
    var res = "";
    res = res + Number.isNaN(123) + ": 123<br>";
    res = res + Number.isNaN(-1.23) + ": -1.23<br>";
    res = res + Number.isNaN(5-2) + ": 5-2<br>";
    res = res + Number.isNaN(0) + ": 0<br>";
    res = res + Number.isNaN('123') + ": '123'<br>";
    res = res + Number.isNaN('Hello') + ": 'Hello'<br>";
    res = res + Number.isNaN('2005/12/12') + ": '2005/12/12'<br>";
    res = res + Number.isNaN('') + ": ''<br>";
    res = res + Number.isNaN(true) + ": true<br>";
    res = res + Number.isNaN(undefined) + ": undefined<br>";
    res = res + Number.isNaN('NaN') + ": 'NaN'<br>";
    res = res + Number.isNaN(NaN) + ": NaN<br>";
    res = res + Number.isNaN(0 / 0) + ": 0 / 0<br>";

    document.getElementById("demo").innerHTML = res;
}
</script>

</body>
</html>