check if number or string javascript code example
Example 1: javascript check if string is number
isNaN(num)
function isNumeric(num){
return !isNaN(num)
}
isNumeric(123)
isNumeric('123')
isNumeric('1e10000')
isNumeric('foo')
isNumeric('10px')
Example 2: javascript is variable a string
if (typeof myVar === 'string'){
}
Example 3: js check if string is number
isNaN(num)
isNaN(123)
isNaN('123')
isNaN('1e10000')
isNaN('foo')
isNaN('10px')
Example 4: 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>