title: change class of current button element
body: <p>My Html</p>
  
  <pre><code>&lt;div onclick="change()" class="button"&gt;ELEMENT 1&lt;/div&gt;
  &lt;div onclick="change()" class="button"&gt;ELEMENT 2&lt;/div&gt;
  &lt;div onclick="change()" class="button"&gt;ELEMENT 3&lt;/div&gt;
  </code></pre>
  
  <p>My Css</p>
  
  <pre><code>.button {
  background-color: #fff;
  color:#000;
  }
  
  .buttonactive {
  background-color: #000;
  color:#fff;
  }
  </code></pre>
  
  <p>My jQuery</p>
  
  <pre><code>function change() {
        $(this).addClass("buttonactive");
  }
  </code></pre>
  
  <p>I want to change the current button to the class buttonactive...</p>