How to validate the given input is a number or not using Javascript?
Contents
isNan() function in Javascript
The function isNan() is used to determines whether a value is not a number. It will returns the true if the value is not a number. Otherwise it returns false which means the given input is a number.
Syntax
isNan(value)The value should be given as parameter in the isNan() function. Then it is tested by isNan() function and returns the true/false value based on the input.
Example for number validation in Javascript
Javascript code with isNan() function
<html>
<head>
</head>
<body>
<form name="testForm">
Mobile Number: <input type="text" id="mnumber" name="mobile">
<input type="submit" value="Submit" onclick="return validatenumber()">
<div id="mylocation"></div>
<div id="mylocation1"></div>
</form>
<script type="text/javascript">
function validatenumber()
{
var mobile_number = document.getElementById("mnumber").value;
if (isNaN(mobile_number))
{
document.getElementById("mylocation").innerHTML="Enter only number";
document.getElementById("mylocation").style.color="Red";
return false;
}
else{
document.write(mobile_number + " is a number <br/>");
return true;
}
}
</script>
</body>
</html>