php 正则html网址代码
$pattern = /[w-]+.(com|net|org|gov|cc|biz|info|cn)(.(cn|hk))*/;
    preg_match($pattern, $url, $matches);
    if(count($matches) > 0) {
        return $matches[0];
    }else{
        $rs = parse_url($url);
        $main_url = $rs[host];
        if(!strcmp(long2ip(sprintf(%u,ip2long($main_url))),$main_url)) {
            return $main_url;
        }else{
            $arr = explode(.,$main_url);
            $count=count($arr);
            $endarr = array(com,net,org,3322);//com.cn  net.cn 等情况
            if (in_array($arr[$count-2],$endarr)){
                $domain = $arr[$count-3]...$arr[$count-2]...$arr[$count-1];
            }else{
                $domain =  $arr[$count-2]...$arr[$count-1];
            }
            return $domain;
        }// end if(!strcmp...)
    }// end if(count...)
}// end function