Hi ankit09,
NEGATIVE_INFINITY is a static property of the JavaScript Number object.
You can only use it as Number.NEGATIVE_INFINITY.
Using x.NEGATIVE_INFINITY, where x is a number or a Number object will return undefined.
Syntax
Number.NEGATIVE_INFINITY;
Example
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script>
window.onload = function () {
alert(Number.NEGATIVE_INFINITY);
var x = 100;
alert(x.NEGATIVE_INFINITY);
}
</script>
</head>
<body>
</body>
</html>
Demo
For more details refer below link.
https://www.w3schools.com/jsref/jsref_negative_infinity.asp