php通过http_user_agent判断用户设备类型(脑残版)

echo getDevice($_SERVER["HTTP_USER_AGENT"]);
function getDevice($agent){
    if(true == preg_match("/.+Windows.+/", $agent)){
        return "web设备";
    }elseif(true == preg_match("/.+Macintosh.+/", $agent)){
        return "mac设备";
    }elseif(true == preg_match("/.+iPad.+/", $agent)){
        return "iPad设备";
    }elseif(true == preg_match("/.+iPhone.+/", $agent)){
        return "iPhone设备";
    }elseif(true == preg_match("/.+Android.+/", $agent)){
        return "Android设备";
    }else{
        return "未知设备";
    }
}