title: jQuery: Append child element before child element
body: <p>I have an HTML code like this:</p>
  
  <pre><code>&lt;div id="content"&gt;
  
      &lt;div class="foobar"&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I want to append child elements inside <code>div#content</code> before the <code>div.foobar</code> element. How can do that?</p>