远程获取web服务器时间

function get_time($server){    

     $data  = "HEAD / HTTP/1.1\r\n";    

     $data .= "Host: $server\r\n";    

     $data .= "Connection: Close\r\n\r\n";    

     $fp = fsockopen($server, 80);    

     fputs($fp, $data);    

     $resp = '';    

     while ($fp && !feof($fp))    

         $resp .= fread($fp, 1024);    
     preg_match('/^Date: (.*)$/mi',$resp,$matches);    

     return strtotime($matches[1]);    

 }   

echo date('Y-m-d H:i:s',get_time("www.sina.com"));