title: jQuery Add Class doesn't work
body: <p>I want to add a class to an object when I click on an div with the class "arrow right" or "arrow left".
  On <a href="http://jsfiddle.net/" rel="nofollow">http://jsfiddle.net/</a> does it work perfect. But on my Site it doesn't work :(</p>
  
  <p>Can anyone help me?</p>
  
  <p>jQuery:</p>
  
  <pre><code>var currentPage = 0;
  var lastPage = ($(".post-preview &gt; div").length)-1;
  currentPage = $('.post-preview &gt; div.show').attr('id');
  
  $('.news &gt; .right').stop().click(function() {
      if (currentPage == lastPage) {
              $('.post-preview &gt; div#' + lastPage).hide();
              $('.post-preview &gt; div#' + lastPage).removeClass('show');
  
          $('.post-preview &gt; div#0').fadeIn(300);
          $('.post-preview &gt; div#0').addClass('show');
          currentPage = 0;
      } else {
          $('.post-preview &gt; div#'+currentPage).hide();
          $('.post-preview &gt; div#'+currentPage).removeClass('show');
          currentPage++;
          var nextPage = currentPage;
          currentPage--;
          $('.post-preview &gt; div#'+nextPage).fadeIn(300);
          $('.post-preview &gt; div#'+nextPage).addClass('show');
          currentPage = nextPage;
      }
   });
  
   $('.news &gt; .left').stop().click(function() {
       if (currentPage == 0) {
          $('.post-preview &gt; div#0').hide();
          $('.post-preview &gt; div#0').removeClass('show');
  
          $('.post-preview &gt; div#' + lastPage).fadeIn(300);
          $('.post-preview &gt; div#' + lastPage).addClass('show');
          currentPage = lastPage;
      } else {
          $('.post-preview &gt; div#'+currentPage).hide();
          $('.rpost-preview &gt; div#'+currentPage).removeClass('show');
          currentPage--;
          var nextPage = currentPage;
          currentPage++;
          $('.post-preview &gt; div#'+nextPage).fadeIn(300);
          $('.post-preview &gt; div#'+nextPage).addClass('show');
          currentPage = nextPage;
      }
  });
  </code></pre>
  
  <p>CSS for show class:</p>
  
  <pre><code>.news &gt; .post-preview &gt; div.show    { display: inline-block !important; }
  </code></pre>
  
  <p>My HTML Code:</p>
  
  <pre><code>&lt;div class="news"&gt;
  &lt;div class="arrow left"&gt;&lt;/div&gt;
      &lt;div class="post-preview"&gt;
          &lt;div id="0" class='show'&gt;&lt;/div&gt;
          &lt;div id="1"&gt;&lt;/div&gt;
          &lt;div id="2"&gt;&lt;/div&gt;
  
      &lt;/div&gt;
  &lt;div class="arrow right"&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>