我创建了一个响应式菜单栏，显示在附加的图像中，它在文件级别工作良好，如下所示：

https://airlineshq.com/airlines/malaysia/index.htm

再往下一级时，

https://airlineshq.com/airlines/malaysia/airasia/index.htm

响应菜单栏仍在工作，但搜索图标、汉堡包3行栏和X栏从未出现。我想是由于文件结构的问题，有人可以帮忙检查吗？

帮助检查下面的脚本以确定是否有任何问题？

<div class="navbar" id="nav">
      <a href="https://airlineshq.com" class="active">Home</a>
     <a href="../../../passenger_guides/index.htm">Passenger Guides</a>
      <a href="../../../airlines/index.htm">Airlines Offices</a>
      <a href="../../../lounges/index.htm">Lounges</a>

      <form class="search-box" action="search.htm">
    <input type="text" placeholder="Search..">
    <button type="submit" class="search-icon"><i class="fa fa-search"></i></button>
    
  </form>
    
  <a href="javascript:void(0);" class="icon" onclick="myFunction()"><i class="fa fa-bars"></i></a>  
</div>
</div>

<script>
    function myFunction() {
      var x = document.getElementById("nav");
      
      console.log(barIcon)
      if (x.className === "navbar") {
        x.className += " responsive";
        var barIcon = document.getElementsByClassName('fa-bars')[0];
        barIcon.classList.add("fa-times");
        barIcon.classList.remove("fa-bars");
      } else {
        var closeIcon = document.getElementsByClassName('fa-times')[0];
        closeIcon.classList.remove("fa-times");
closeIcon.classList.add("fa-bars");
        x.className = "navbar";
      }
    }  
</script>   

顺晟科技：

下一级可能没有通往Fontawesome的正确路径

顶层：

下一级