URL Validation in Php

[jaga]

<?php
$subscr=$_REQUEST['subscr'];

//url validation

if (preg_match('|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i', $subscr))
{
print "$subscr url OK.";
} else {
print "$subscr url not valid!";
}
//echo("$subscr");
?>