php实现扫描二维码根据浏览器类型访问不同下载地址

<?php
$agent = $_server['http_user_agent'];
preg_match('/android|iphone/i',$agent,$matches);
if (strtolower($matches[0]) == 'android') {
// echo "安卓";
header("location: ".$globals["public_appconfig"]["app"]['android']."'");
} elseif (strtolower($matches[0]) == 'iphone') {
header("'location: ".$globals["public_appconfig"]["app"]['ios']."'");
}else{
//不确定是什么系统或者是pc
header("location: ".$globals["public_appconfig"]["app"]['android']."'");
}
?>