- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$s = "http://ad.zanox.com/ppc/?23012557C80290415&ULP=[[0000011028nubuck%20kaki&eurl=http%3A%2F%2Fwww.sarenza.nl%2Fbirkenstock-madrid-flor-w-s780328-p0000011028]]";
//$t = stristr($s,"&eurl",true);
//str_replace("[[","",stristr($t,"[["));
preg_match('\(prdref=)(.*?)(&eurl)',$s,$match);
var_dump($match);
?>