PHP判断电脑端和手机端显示不同内容

<?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()){
// 手机端
echo '
手机端显示内容
';

}else{
// 电脑端
echo '
电脑端显示内容
';

}
 ?>