我有一个home_controller index action. 并且是首页 root 'home#index'.

index 这个首页上有个按钮，当点击的时候调用 js 代码（coffee）里面的代码来弹窗。

但是直接打开 localhost 时候没有反应，点击下菜单的 Home 时候再次点击这个按钮 coffee 代码被正常调用。不知道原因求高手指点。

菜单 application.html.erb

<nav>
<li><%= link_to "Home", "/"%></li>
</nav>

index.html.erb

<button id="myBtn">Open Modal</button>
<div id="myModal" class="modal">
  <div class="modal-content">
    <span class="close">×</span>
    <p>Some text in the Modal..</p>
  </div>
</div>
<%= render :partial => 'stories/stories' %>

home.coffee

modal = document.getElementById('myModal');
btn = document.getElementById("myBtn");
span = document.getElementsByClassName("close")[0];
btn.onclick = ->
    modal.style.display = "block"
span.onclick = ->
    modal.style.display = "none"
window.onclick = (event) ->
    modal.style.display = "none" if event.target == modal