how to check if variable is a number javascript code example
Example 1: javascript check if variable is number
function isNumber(n) {
return !isNaN(parseFloat(n)) && !isNaN(n - 0);
}
Example 2: check if something is a number
<html>
<head></head>
<body>
<h1>isNaN() example</h1>
<script type="text/javascript">
var num1 = 100;
if(isNaN(num1)){
document.write(num1 + " is not a number <br/>");
}else{
document.write(num1 + " is a number <br/>");
}
var str1 = "mkyong"
if(isNaN(str1)){
document.write(str1 + " is not a number <br/>");
}else{
document.write(str1 + " is a number <br/>");
}
</script>
</body>
</html>
Example 3: js is variable int
// The === operator is used for checking
// the value and the type of a variable
var data = 1;
if (data === parseInt(data, 10))
alert("data is integer")
else
alert("data is not an integer")