PHP를 JS 코드로 변환하는 방법

<?php
$user_agent = $_SERVER[&#39;HTTP_USER_AGENT&#39;];
if (strpos($user_agent, &#39;MicroMessenger&#39;) === false) {
// 非微信浏览器禁止浏览
echo "HTTP/1.1 401 Unauthorized";
} else {
// 微信浏览器，允许访问
echo "MicroMessenger";
// 获取版本号
preg_match(&#39;/.*?(MicroMessenger\/([0-9.]+))\s*/&#39;, $user_agent, $matches);
echo &#39;<br>Version:&#39;.$matches[2];
}

with(navigator){
    if(appName != 'MicroMessenger'){
        document.write('非微信浏览器');
    }else{
        document.write(&#39;MicroMessenger</br>&#39;+appVersion);
    }
 
}