菜单按钮不在引导程序上工作

Question

我在html中有这个代码。调整大小后，菜单按钮将出现，但如果单击它将不会切换或显示菜单列表。

CODE

<div class="navbar navbar-default navbar-fixed-top"  id="navHead">
    <div class="container">
      <div class="navbar-header">
        <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
          <span class="sr-only">Toggle navigation</span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
        </button>
        <a class="navbar-brand" href="#">USJ-R Online Enrolment System</a>
      </div>
      <div class="collapse navbar-collapse">
        <ul class="nav navbar-nav">
          <li><a href="StudentPage.aspx">Home</a></li>
          <li><a href="SubjectOffered.aspx">Subject Offered</a></li>
            <li class="active"><a href="ApprovalArea.aspx">Approval Area</a></li>
          <li><a runat="server" onserverclick="logout_Click" class="navbar-link">Logout</a>&nbsp;</li>
        </ul>
      </div><!--/.nav-collapse -->
    </div>
  </div>