試圖添加底紋到選定的引導程序3導航欄

我做了一個Navbar的引導程序3.我的問題是如何讓它被選中時着色？一切工作正常否則。我相信它需要一些JavaScript，但我不知道如何實現它。試圖添加底紋到選定的引導程序3導航欄

這是我的代碼：

<nav class="navbar navbar-default navbar-fixed-top" role="navigation"> 
    <!-- Brand and toggle get grouped for better mobile display --> 
    <div class="navbar-header"> 
    <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-ex1-collapse"> 
     <span class="sr-only">Toggle navigation</span> 
     <span class="icon-bar"></span> 
     <span class="icon-bar"></span> 
     <span class="icon-bar"></span> 
    </button> 
    <div style="font-family:Webdings;"> 
     <%= link_to "lalala", root_path, class: 'navbar-brand' %> 
    </div> 
    </div> 
    <!-- Collect the nav links, forms, and other content for toggling --> 
    <div class="collapse navbar-collapse navbar-ex1-collapse"> 
    <ul class="nav navbar-nav"> 
     <li><%= link_to "laaa", lal_path %></li> 
     <li class="dropdown"> 
     <a href="#" class="dropdown-toggle" data-toggle="dropdown">lala<b class="caret"></b></a> 
     <ul class="dropdown-menu"> 
      <li><%= link_to "lala", laa_path %></li> 
      <li><%= link_to "lalala", lala_path %></li> 
      <li><%= link_to "lalala", lala_path %></li> 
     </ul> 
     </li> 
    </ul> 
    <ul class="nav navbar-nav navbar-right"> 
     <li> 
     <a href="https:lalala" class="twitter-follow-button" data-show-count="false" data-show-screen-name="false">Follow @lalala</a> 
     </li> 
     <li> 
     <div class="fb-like" data-href="lalala" data-width="600" data-layout="button_count" data-show-faces="true" data-send="false"></div> 
     </li> 
     <li><%= link_to "lala", contact_path %></li> 
     <li><%= link_to "lalalala", register_path %></li> 
    </ul> 
    </div><!-- /.navbar-collapse --> 
</nav>

來源

2014-01-06 user3167011