- substr: documentation ( source)
- print_r: documentation ( source)
- strripos: documentation ( source)
<?php
$domain = 'http://domain.de/kontkt/index.php';
$pos_slash = strripos($domain, "/");
$root_url = substr($domain, 0, $pos_slash);
$root_url = $root_url.'/';
print_r($root_url);