php如何判断是手机访问还是电脑访问网站

<?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";
}
?>

<?php
function isMobile(){ 
 $useragent=isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : ''; 
 $useragent_commentsblock=preg_match('|(.*?)|',$useragent,$matches)>0?$matches[0]:''; 
 function CheckSubstrs($substrs,$text){ 
 foreach($substrs as $substr) 
 if(false!==strpos($text,$substr)){ 
 return true; 
 } 
 return false; 
 }
 $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,$useragent_commentsblock) || 
 CheckSubstrs($mobile_token_list,$useragent); 
 
 if ($found_mobile){ 
 return true; 
 }else{ 
 return false; 
 } 
}
if (isMobile())
 echo '手机登录';
else
 echo '电脑登录';
?>