$reqWebSite = 'csdn.net';
$str = "url=http://www.csdn.net,程序员技术社区";
if(preg_match('/url\=(http\:\/\/www\.'.preg_quote($reqWebSite).')\,(.*)/i',$str,$match)) print_r($match);
$str = "url=http://www.csdn.net,程序员技术社区";
if(preg_match('/url\=(http\:\/\/www\.'.preg_quote($reqWebSite).')\,(.*)/i',$str,$match)) print_r($match);
$str = 'url=http://community.csdn.net/Expert/topic/5315/5315538.xml, 程序员技术社区';
$pattern = '/url=(.*'.preg_quote($search).'.*),(.+)/i';
if(preg_match($pattern,$str,$match))
{
echo $match[1].'<br>'.$match[2];
}