- parse_str: documentation ( source)
- parse_url: documentation ( source)
<?php
$url = "http://www.youtube.com/watch?h=C4kxS1ksqtw&feature=relate";
parse_str( parse_url( $url, PHP_URL_QUERY ), $my_array_of_vars );
if(isset($my_array_of_vars['v']))echo $my_array_of_vars['v'];
// Output: C4kxS1ksqtw
?>