PHP determines if a user is accessing a mobile phone

$agent=Check_wap ();if($agent ){    Header(' location:http://www.lewanau.com '); Exit;}//Check if WAPfunctionCheck_wap () {//first check whether it is a WAP proxy, high accuracy    if(Stristr($_server[' Http_via '], "WAP")){        return true; }    //Check if the browser accepts WML.    ElseIf(Strpos(Strtoupper($_server[' http_accept ']), "VND. Wap. WML ") > 0){        return true; }   //Check User_agent   ElseIf(Preg_match('/(blackberry|configuration\/cldc|hp |hp-|htc |htc_|htc-|iemobile|kindle|midp|mmp|motorola|mobile|nokia|opera Mini|opera | googlebot-mobile| yahooseeker\/m1a1-r2d2|android|iphone|ipod|mobi|palm|palmos|pocket|portalmmm|ppc;|smartphone|sonyericsson|sqh| Spv|symbian|treo|up.browser|up.link|vodafone|windows ce|xda |xda_)/I ',$_server[' Http_user_agent '])){        return true; }    Else{        return false; }}

PHP determines if a user is accessing a mobile phone