<html>
<body>
<h1>JavaScript Global Methods</h1>
<h2>The isNaN() Method</h2>
<p>isNaN() returns true if a value is NaN:</p>
<p id="demo"></p>
<script>
let result =
"Is 0/0 NaN? " + isNaN(0/0) + "<br>" +
"Is ' ' NaN? " + isNaN(' ') + "<br>" +
"Is 'A' NaN? " + isNaN('A') + "<br>" +
"Is true NaN? " + isNaN(true) + "<br>" +
"Is false NaN? " + isNaN(false);
document.getElementById("demo").innerHTML = result;
</script>
</body>
</html>