menu.html

<div class="navbar navbar-inverse">
  <div class="navbar-header">
    <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-responsive-collapse">
      <span class="icon-bar"></span>
      <span class="icon-bar"></span>
      <span class="icon-bar"></span>
    </button>
  </div>
  <div class="navbar-collapse collapse navbar-responsive-collapse">
    <ul class="nav navbar-nav">
      {% if page.layout == "homepage" %}
      <li class="active">
      {% else %}
      <li>
      {% endif %}
        <a href="/">Home</a>
      </li>
      {% for item in site.data.menu.toc %}
      {% if item.subfolderitems %}
      {% if page.section == item.title %}
      <li class="active dropdown">
      {% else %}
      <li class="dropdown">
      {% endif %}
        <a href="#" class="dropdown-toggle" data-toggle="dropdown">{{ item.title }} <b class="caret"></b></a>
        <ul class="dropdown-menu">
          {% for entry in item.subfolderitems %}
          <li><a href="{{ entry.url }}">{{ entry.page }}</a></li>
          {% endfor %}
        </ul>
      {% else %}
      {% if page.title == item.title %}
      <li class="active">
      {% else %}
      <li>
      {% endif %}
        <a href="{{ item.url }}">{{ item.title }}</a>
      {% endif %}
      </li>
      {% endfor %}
    </ul>
  </div>
</div>
<noscript>
  <div class="row">
    <div class="col-md-4"></div>
    <div class="col-md-4">
      <p>&nbsp;</p>
      <p>&nbsp;</p>
      <p>&nbsp;</p>
      <p>&nbsp;</p>
      <p>JavaScript is disabled but this website works best with JavaScript enabled.</p>
    </div>
  </div>
</noscript>