PHP判断PC或者手机

1. $ua = strtolower($_SERVER['HTTP_USER_AGENT']);  
2.           
3. $uachar = "/(nokia|sony|ericsson|mot|samsung|sgh|lg|philips|panasonic|alcatel|lenovo|cldc|midp|mobile|ipad|iphone|android)/i";  
4. if(preg_match($uachar, $ua))  
5. {  
6.     if(!empty($_SERVER['REQUEST_URI'])){//手机访问，跳转至手机版对应的页面  
7.         $localurl = $URL.$_SERVER['REQUEST_URI'];  
8.         header("Location: $localurl");   
9.     }else{  
10.         header("Location: $URL"); //PC  
11.     }  
12. }