Javascript 导航栏下拉按钮在twitter引导中不起作用

我对twitter bootstrap很陌生，我的网站在桌面等大屏幕上运行良好，但当我调整浏览器的大小以获得移动屏幕的效果时，它并没有显示允许我们选择导航栏的图标下拉列表

      <div class="row nav-menu">



        <a href="/">
          <div class="col-md-2 col-sm-3 columns">
              <img class="logo logo-light logo-wide" alt="Logo" src="img/logo_t.png">
              <img class="logo logo-dark logo-wide" alt="Logo" src="img/logo_t.png">
          </div>
        </a>

          <div class="nav-header">
              <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#navigationbar">
               <span class="icon-bar">About</span>
               <span class="icon-bar">Technology</span>
               <span class="icon-bar has-dropdown">API</span>
               <span class="icon-bar">News</span>
               <span class="icon-bar">Jobs</span>
               <span class="icon-bar">Contacts</span>
            </button>

          </div>

           <div class="col-md-10 col-sm-9 columns ">
            <ul class="menu navigationbar">
            <li><a href="/about">About</a></li>
            <li><a href="/technology">Technology</a></li>
            <li class="has-dropdown">
                <a href="#">API <span class="glyphicon glyphicon-chevron-down"></span></a>
              <ul class="subnav">
                <li><a href="/api">Plans</a></li>
                <li><a href="">Documentation</a></li>
                <li><a href="">Login</a></li>
              </ul>

            </li>
            <li><a href="/news">News</a></li>
            <li><a href="/jobs">Jobs</a></li>
            <li><a href="/contact">Contact</a></li>
          </ul>
        </div>

      </div>


       <div class="mobile-toggle">



      </div>

    </div>
  </nav>
</div>  <!-- navbar end -->

HTML

      <div class="row nav-menu">



        <a href="/">
          <div class="col-md-2 col-sm-3 columns">
              <img class="logo logo-light logo-wide" alt="Logo" src="img/logo_t.png">
              <img class="logo logo-dark logo-wide" alt="Logo" src="img/logo_t.png">
          </div>
        </a>

          <div class="nav-header">
              <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#navigationbar">
               <span class="icon-bar">About</span>
               <span class="icon-bar">Technology</span>
               <span class="icon-bar has-dropdown">API</span>
               <span class="icon-bar">News</span>
               <span class="icon-bar">Jobs</span>
               <span class="icon-bar">Contacts</span>
            </button>

          </div>

           <div class="col-md-10 col-sm-9 columns ">
            <ul class="menu navigationbar">
            <li><a href="/about">About</a></li>
            <li><a href="/technology">Technology</a></li>
            <li class="has-dropdown">
                <a href="#">API <span class="glyphicon glyphicon-chevron-down"></span></a>
              <ul class="subnav">
                <li><a href="/api">Plans</a></li>
                <li><a href="">Documentation</a></li>
                <li><a href="">Login</a></li>
              </ul>

            </li>
            <li><a href="/news">News</a></li>
            <li><a href="/jobs">Jobs</a></li>
            <li><a href="/contact">Contact</a></li>
          </ul>
        </div>

      </div>


       <div class="mobile-toggle">



      </div>

    </div>
  </nav>
</div>  <!-- navbar end -->

---

请提供帮助，谢谢。

对于bootstrap，您的include看起来像什么？要指定@Deepak问题：您是否包括bootstrap.js文件？

      <div class="row nav-menu">



        <a href="/">
          <div class="col-md-2 col-sm-3 columns">
              <img class="logo logo-light logo-wide" alt="Logo" src="img/logo_t.png">
              <img class="logo logo-dark logo-wide" alt="Logo" src="img/logo_t.png">
          </div>
        </a>

          <div class="nav-header">
              <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#navigationbar">
               <span class="icon-bar">About</span>
               <span class="icon-bar">Technology</span>
               <span class="icon-bar has-dropdown">API</span>
               <span class="icon-bar">News</span>
               <span class="icon-bar">Jobs</span>
               <span class="icon-bar">Contacts</span>
            </button>

          </div>

           <div class="col-md-10 col-sm-9 columns ">
            <ul class="menu navigationbar">
            <li><a href="/about">About</a></li>
            <li><a href="/technology">Technology</a></li>
            <li class="has-dropdown">
                <a href="#">API <span class="glyphicon glyphicon-chevron-down"></span></a>
              <ul class="subnav">
                <li><a href="/api">Plans</a></li>
                <li><a href="">Documentation</a></li>
                <li><a href="">Login</a></li>
              </ul>

            </li>
            <li><a href="/news">News</a></li>
            <li><a href="/jobs">Jobs</a></li>
            <li><a href="/contact">Contact</a></li>
          </ul>
        </div>

      </div>


       <div class="mobile-toggle">



      </div>

    </div>
  </nav>
</div>  <!-- navbar end -->