php判断当前的访问是手机还是电脑

<?php
function check_wap() {
    if (isset($_SERVER['HTTP_VIA'])) return true;
    if (isset($_SERVER['HTTP_X_NOKIA_CONNECTION_MODE'])) return true;
    if (isset($_SERVER['HTTP_X_UP_CALLING_LINE_ID'])) return true;
    if (strpos(strtoupper($_SERVER['HTTP_ACCEPT']),"VND.WAP.WML") > 0) {
        // Check whether the browser/gateway says it accepts WML.
        $br = "WML";
    } else {
        $browser = isset($_SERVER['HTTP_USER_AGENT']) ? trim($_SERVER['HTTP_USER_AGENT']) : '';
        if(empty($browser)) return true;
        $mobile_os_list=array('Google Wireless Transcoder','Windows CE','WindowsCE','Symbian','Android','armv6l','armv5','Mobile','CentOS','mowser','AvantGo','Opera Mobi','J2ME/MIDP','Smartphone','Go.Web','Palm','iPAQ');  

        $mobile_token_list=array('Profile/MIDP','Configuration/CLDC-','160×160','176×220','240×240','240×320','320×240','UP.Browser','UP.Link','SymbianOS','PalmOS','PocketPC','SonyEricsson','Nokia','BlackBerry','Vodafone','BenQ','Novarra-Vision','Iris','NetFront','HTC_','Xda_','SAMSUNG-SGH','Wapaka','DoCoMo','iPhone','iPod');  

        $found_mobile=checkSubstrs($mobile_os_list,$browser) ||
                  checkSubstrs($mobile_token_list,$browser);
    if($found_mobile)
      $br ="WML";
    else $br = "WWW";
    }
    if($br == "WML") {
        return true;
    } else {
        return false;
    }
}

function checkSubstrs($list,$str){
  $flag = false;
  for($i=0;$i<count($list);$i++){
    if(strpos($str,$list[$i]) > 0){
      $flag = true;
      break;
    }
  }
  return $flag;
}

if(check_wap()){
  　echo "wap";
}else{
　　echo "web";
}

?>