PHP判断设备类型

/**
 * 用于判断设备
 */
function equipment(){
    $UserAgent=$_SERVER['HTTP_USER_AGENT'];
    if(strstr($UserAgent,'Android')){
        return "Android";
    }elseif(strstr($UserAgent,'iPhone')){
        return "iPhone";
    }else{
        return "PC";
    }
}