isNaN-1

NaN stands for Not a Number, so isNaN function will tell whether the passed value is not a number OR number. This is how we can pass the value in isNaN function and get the output: isNaN(NaN) , isNaN(undefined) , isNaN(null) , isNaN(37) will result in true,true,false and false.

<!DOCTYPE html>
<html>
<head>
<title>Welcome to LearnKode - A code learning platform</title>
     
</head>
<body>
<p>The isNaN() function returns true if the value is NaN (Not-a-Number), and false if not.</p>
<button onclick="checkNumber()">Check the value</button>
<p id="sample"></p>
<script>
function checkNumber() {
    var a = isNaN(NaN) + "<br>";
    var b = isNaN(undefined) + "<br>";
    var c = isNaN(null) + "<br>";
    var d = isNaN(37) + "<br>";
     numbers=a+b+c+d;
     document.getElementById("sample").innerHTML = numbers;
}
</script>

</body>
</html>

Output