PHP如何识别是电脑端或手机移动端访问网站

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