PHP如何识别是电脑或手机访问网站

现在通过手机访问网站越来越流行了，如果我们希望统计一下网站通过pc，手机移动端的各自访问量的情况，或者需要为手机移动端做一些特别的处理的话，那么我们就需要对访问网站的用户的客户端做一下鉴别了，下面这个实例就是通过php识别用户是电脑还是手机访问网站的方法。

<?php
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.maopiaopiao.com';
}else{
    echo '电脑登录 www.maopiaopiao.com';
}