title: How to add property to existing class
body: <p>I have got a CSS class like so: </p>
  
  <pre><code>.simpleClass {
      width: 25px;
  }
  </code></pre>
  
  <p>And I have a matching element:</p>
  
  <pre><code>&lt;div class="simpleClass"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>Can I add the property <code>display: none;</code> to the CSS class <code>.simpleClass</code> dynamically  through jQuery? Thanks.</p>