title: Zurb Foundation dropdown menu doesn't work
body: <p>I got this error when clicking on my dropdown menu on the zurb top bar:</p>
  
  <pre><code>event.returnValue is deprecated. Please use the standard event.preventDefault() instead. 
  </code></pre>
  
  <p>Here is my application.js:</p>
  
  <pre><code>//= require jquery
  //= require jquery_ujs
  //= require foundation
  //= require_tree .
  
  $(function(){ $(document).foundation(); });
  </code></pre>
  
  <p>and in my view (slim template):</p>
  
  <pre><code>  nav class="top-bar"
      ul class="title-area"
        li class="name"
          h1
            a href="#" My Project
        li class="toggle-topbar menu-icon"
          a href="#" Menu
      section class="top-bar-section"
        ul class="left"
          li class="divider"
          li class="divider hide-for-small"
        ul class="right"
          li class="divider show-for-medium-and-up"
            - if current_user
              li class="has-dropdown"
                a href="#"
                  = "Logged in as #{current_user.email}"
                ul class="dropdown"
                  li
                    a href="#"
                      ' First link in dropdown
              li
                = link_to "Log Out", logout_path
            - else
              li
                = link_to t("layout.login"), login_path
              li
                = link_to t("layout.signup"), signup_path
  </code></pre>
  
  <p>The dropdown menu doesn't work (it doesn't appear when clicking or hovering)</p>