The following code shows how to Find Reverse of a Number in JavaScript
<html>
<head>
<title>Reverse of a Number</title>
<script>
var num;
num=prompt("Enter a number: ");
len=num.length;
num=Number(num);
var n=num;
var sum=0;
var i=len-1;
while(n>0)
{
var rem=n%10;
sum=sum+rem*Math.pow(10, i);
n=Math.floor(n/10);
i=i-1;
}
document.write("Original Number: "+num+"<br/>Reversed Number: "+sum);
</script>
</head>
<body>
</body>
</html>
Output
Further Reading
Evolution of JavaScript from ES1 to ES2020