Url Validation

we can also validate our url by use following regular expression:

<?php

 $weburl= test_input($_POST["url"]);

if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$weburl)) {

  $weburlErr= "Invalid URL"; 

}

?>