PHP 判断访问来源是否来自手机并跳转页面

$ua = strtolower($_SERVER['HTTP_USER_AGENT']); 

$uachar = "/(nokia|sony|ericsson|mot|samsung|sgh|lg|philips|panasonic|alcatel|lenovo|cldc|midp|mobile)/i"; 

if(($ua == '' || preg_match($uachar, $ua))&& !strpos(strtolower($_SERVER['REQUEST_URI']),'wap')) { 

   $Loaction = 'mobile/'; 

if (!empty($Loaction)) { 

   header("Location: $Loaction\n"); 

   exit; 

   }

}