PHP识别用户访问来自PC端还是手机移动端

现在手机移动端的开发愈演愈烈，作为PHP的开发者们怎么也不能停下步伐；
未来的手机(移动端)站点开发也是一个趋势，做好有备无患的准备，面对未来的发展....

废话不多说，代码非原创，重在分享；

<?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m.Vevb.com'; 
else 
    echo '电脑登录blog.Vevb.com'; 
?>