PHP Example
Screen shot
Integer value validation

<?php
if(isset($_POST['btn']))
{
if(strcmp($_POST['age'],strval(intval($_POST['age']))))
echo "Age should be numeric";
}
?>
<html>
<head>
<title>php example</title>
</head>
<body>
<form name="frm" action="" method="post">
Enter Age<input name="age" type="text" /><br />
<input name="btn" type="submit" value="Submit" />
</form>
</body>
</html>

You can download source code here