Find link i streng

<?php
function GetUrl($string){
    $ar=explode(' ', $string);
    $lng=count($ar);
    $rest="";
    for($j=0;$j<$lng; $j++){        
        $str=stristr($ar[$j], "href=");            
        if(strlen($str)>0){
            $rest = substr($str, 6, -1);            
            break;
        }    
    }
    return $rest;    
}
// $string = '<a class="read_more" href="http://olsensweb.dk" title="opskrifter !">Read more...</a>';
// $string = '<a href="http://olsensweb.dk" class="read_more" title="opskrifter !">Read more...</a>';
// $string = '<a title="opskrifter" href="http://it-k.dk/dynamisk-web-nu-ogs%C3%A5-til-mobil" >Read more...</a>';
$string = '<a title="opskrifter" href="http://www.google.com/?var=234&key=234" >Read more...</a>';
echo GetUrl($string);
?>