title: How to change css attribute of a class
body: <p>I have <code>&lt;span&gt;</code> inside a <code>&lt;div&gt;</code>, like so:</p>
  
  <pre><code>&lt;div id="#mydiv"&gt;
  &lt;a href="#"&gt;Hello&lt;/a&gt;&lt;span class="myImageArea"&gt;&lt;/span&gt;
      &lt;div class="someClass"&gt;
      &lt;/div&gt;
  &lt;/div&gt;                          
  </code></pre>
  
  <p>With the following CSS:</p>
  
  <pre><code>.myImageArea {  
      background: url("../img/upArrow.png") no-repeat right 5px;
      display: inline-block;
      cursor: pointer;
  }
  </code></pre>
  
  <p>I want to change the attribute <code>background:url</code> of class <code>myImageArea</code></p>
  
  <pre><code>$('#mydiv').click(function() {
      //change the background image of the class
  });
  </code></pre>
  
  <p>How can this be done?</p>