php determines whether mobile access or computer access sample sharing

<?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 x 160','176 x 220','240 x 240','240 x 320','320 x 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 ' Mobile phone login m.jb51.com';
else
 echo ' Computer login www.jb51.com';
?>