title: how to replace all <a> hrefs within div element?
body: <p>Replace all href's within a div element by adding <a href="http://mysite.com?url=" rel="nofollow">http://mysite.com?url=</a> infront for example. if the html is...</p>
  
  <pre><code>&lt;div class="post-body"&gt;
  &lt;a href="http://www.google.com"&gt;google&lt;/a&gt;
  &lt;a href="http://www.youtube.com"&gt;youtube&lt;/a&gt;
  &lt;a href="http://www.facebook.com"&gt;facebook&lt;/a&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>replace each href by adding <a href="http://mysite.com?url=" rel="nofollow">http://mysite.com?url=</a> infront so the outcome of the html will be...</p>
  
  <pre><code>&lt;div class="post-body"&gt;
  &lt;a href="http://mysite.com?url=http://www.google.com"&gt;google&lt;/a&gt;
  &lt;a href="http://mysite.com?url=http://www.youtube.com"&gt;youtube&lt;/a&gt;
  &lt;a href="http://mysite.com?url=http://www.facebook.com"&gt;facebook&lt;/a&gt;
  &lt;/div&gt;
  </code></pre>