<html>
<head>
<meta charset="UTF-8">
<title>ssn Checker</title>
<script type="text/javascript">
var Pattern= (\d+(\.\d+)?%);
function checkPercentage(Percentage){
if (Pattern.test(Percentage)) {
alert("VALID Percentage");
} else {
alert("INVALID Percentage");
}
}
</script>
</meta></head>
<body>
<form önsubmit="return false;">
<input type="text" name="Percentage" size="20">
<input type="button" value="Check">
onclick="checkPercentage(this.form.Percentage.value);">
</input></input></form>
</body>
</html>
Second way, You can use Dotnet validation control(regular expression). Define your regex expression in the properties and Customize it as per your requirement.
Regular expression for your query:
(\d+(\.\d+)?%)
^0*(100\.00|[0-9]?[0-9]\.[0-9]{2})%$