function is_mobile() { 
  $user_agent = $_SERVER['HTTP_USER_AGENT']; 
  $mobile_agents = array("240x320","acer","acoon","acs-","abacho","ahong","airness","alcatel","amoi", 
  "android","anywhereyougo.com","applewebkit/525","applewebkit/532","asus","audio", 
  "au-mic","avantogo","becker","benq","bilbo","bird","blackberry","blazer","bleu", 
  "cdm-","compal","coolpad","danger","dbtel","dopod","elaine","eric","etouch","fly ", 
  "fly_","fly-","go.web","goodaccess","gradiente","grundig","haier","hedy","hitachi", 
  "htc","huawei","hutchison","inno","ipad","ipaq","iphone","ipod","jbrowser","kddi", 
  "kgt","kwc","lenovo","lg ","lg2","lg3","lg4","lg5","lg7","lg8","lg9","lg-","lge-","lge9","longcos","maemo", 
  "mercator","meridian","micromax","midp","mini","mitsu","mmm","mmp","mobi","mot-", 
  "moto","nec-","netfront","newgen","nexian","nf-browser","nintendo","nitro","nokia", 
  "nook","novarra","obigo","palm","panasonic","pantech","philips","phone","pg-", 
  "playstation","pocket","pt-","qc-","qtek","rover","sagem","sama","samu","sanyo", 
  "samsung","sch-","scooter","sec-","sendo","sgh-","sharp","siemens","sie-","softbank", 
  "sony","spice","sprint","spv","symbian","tablet","talkabout","tcl-","teleca","telit", 
  "tianyu","tim-","toshiba","tsm","up.browser","utec","utstar","verykool","virgin", 
  "vk-","voda","voxtel","vx","wap","wellco","wig browser","wii","windows ce", 
  "wireless","xda","xde","zte"); 
  $is_mobile = false; 
  foreach ($mobile_agents as $device) { 
    if (stristr($user_agent, $device)) { 
      $is_mobile = true; 
      break; 
    } 
  } 
  return $is_mobile; 
} 

 
if (is_mobile()) { 
  header('Location:http://m.jb51.net'); 
} else { 
  echo '请使用手机访问.'; 
} 

 
if ((navigator.userAgent.match(/(iPhone|iPod|Android|ios|iOS|iPad|Backerry| 
WebOS|Symbian|Windows Phone|Phone)/i))) { 
  location.replace("http://m.jb51.net") 
}else{ 
  document.write("请使用手机访问."); 
}