title: jQuery addClass loop starting from last-child up
body: <p>Every thing works as far as every 500 milliseconds it adds a class to the next blockWrap element in line. </p>
  
  <p>But what I want it to do is start with the last "blockWrap" element, add the class and then work its way up. How can I achieve this?</p>
  
  <p>here is my HTML:</p>
  
  <pre><code>&lt;div class="blockWrap"&gt;
      &lt;div class="blockImg"&gt;
        &lt;img src="img/download.jpg"&gt;
      &lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="blockWrap"&gt;
      &lt;div class="blockImg"&gt;
        &lt;img src="img/download.jpg"&gt;
      &lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="blockWrap"&gt;
      &lt;div class="blockImg"&gt;
        &lt;img src="img/download.jpg"&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  </code></pre>
  
  <p>Here is my jQuery loop:</p>
  
  <pre><code>$(document).ready(function(){
    $(function () {
      var block = $('.blockWrap');
      (function _loop(wrap) {
        block.eq(wrap).addClass('slideIn');
        setTimeout(function () {
          _loop((wrap + 1) % block.length);
        }, 500);
      }(0));
    });
  });
  </code></pre>
  
  <p>Thanks for your help.</p>