title: bootstrap 3 tabs not working properly
body: <p>I almost copied the code from their website. The tab is initiated perfectly, and when I click on tabs, new panels are activated. However, the "active" class is not applied to the activated tab.
  This is the code:</p>
  
  <pre><code>&lt;ul class="nav nav-tabs"&gt;
   &lt;li data-toggle="tab"  data-target="#a" class="active"&gt;&lt;a href="#"&gt;a&lt;/a&gt;&lt;/li&gt;
    &lt;li data-toggle="tab"  data-target="#b" &gt;&lt;a href="#"&gt;b&lt;/a&gt;&lt;/li&gt;
    &lt;li data-toggle="tab"  data-target="#c"  &gt;&lt;a href="#"&gt;c&lt;/a&gt;&lt;/li&gt;
  &lt;/ul&gt;
  
   &lt;div class="tab-content"&gt;
    &lt;div class="tab-pane fade in active" id="a"&gt; in tab a &lt;/div&gt;
    &lt;div class="tab-pane fade" id="b"&gt;in tab b&lt;/div&gt;
    &lt;div class="tab-pane fade" id="c"&gt;in tab c&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>