title: click the image and remove the active class
body: <p>Is there a way where it is possible to remove the active class on red btn when I click on my img and then make blue btn class active?</p>
  
  <p>HTML</p>
  
  <pre><code>&lt;div id="nav"&gt;
  &lt;ul&gt;
  &lt;li class="red btn"&gt;&lt;a class="tildig" href="#din_app" data-transition="fade" &gt;
    &lt;p&gt;TIL DIG&lt;/p&gt;
    &lt;/a&gt;&lt;/li&gt;
  &lt;li class="blue btn"&gt;&lt;a class="kontakt" href="#kontakt" data-transition="fade" &gt;
    &lt;p&gt;KONTAKT&lt;/p&gt;
    &lt;/a&gt;&lt;/li&gt;
  &lt;/ul&gt;
  &lt;/div&gt;
  
  &lt;div data-role="page" id="interesseret"&gt;
  &lt;div data-role="header" data-nobackbtn="true"&gt; &lt;/div&gt;
  &lt;div data-role="content"&gt;
  &lt;p class="brod"&gt;  
  &lt;a href="#kontakt" data-transition="fade"&gt;&lt;img class="kontakt_link_480" src="image/link_img.png" width="480" height="100" alt="Tryk p&amp;aring; kontakt og book et m&amp;oslash;de" &gt;&lt;/a&gt;&lt;/p&gt;
  &lt;/div&gt;
  &lt;div data-role="footer"&gt; &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Script</p>
  
  <pre><code>&lt;script type="application/x-javascript"&gt;
  $(function() {
        $('li.btn').click(function(){
            // Add "active" to the clicked element and
            // get all siblings and remove "active" from them
            $(this).addClass('active').siblings().removeClass('active');
        });
  
      });
  </code></pre>
  
  <p></p>
  
  <p>CSS</p>
  
  <pre><code>.red.btn { float:left; margin: 0 0 0 5px ; width: 40%; height:30px; background-image:url(../image/rod_bnt.png);}
  .red.btn.active { background-image:url(../image/red.jpg); height: 40px; background-position:center;}
  
  .blue.btn {float:right; margin:0 5px 0 0; height:30px; width: 40%; background-image:url(../image/blaa_bnt.png); }
  .blue.btn.active { background-image:url(../image/blue.jpg); height: 40px; background-position:center;}
  </code></pre>
  
  <p>I tried this but it does not work</p>
  
  <pre><code> &lt;script type="application/x-javascript"&gt;
   $(function() {
        $('a.img').click(function(){
            // Add "active" to the clicked element and
            // get all siblings and remove "active" from them
            $(this).addClass('blue.btn.active').siblings().removeClass('red.btn.active');
        });
  
      });
  
   &lt;/script&gt;
  </code></pre>
  
  <p>// thanks in advance Kasper.</p>