title: Display a class using :after
body: <p>I have a simple problem here. What I need to do is that I need to place a class after span in a button. Like if: </p>
  
  <pre><code>&lt;button class="test-button"&gt; 
  &lt;span&gt;This is button&lt;/span&gt;
  &lt;/button&gt;
  
  &lt;span class="custom"&gt; I need to place this after Test button using :after &lt;/span&gt;
  </code></pre>
  
  <p>So if its not clear, I need to place the custom class after the span of text-button class. I was trying to accomplish this by using </p>
  
  <pre><code>.test-button span:after {
      content:attr([class=".custom"]);
  }
  </code></pre>
  
  <p>but its not working ...</p>