title: Replace innerHTML in one element with the innerHTML from another with Javascript
body: <p>I would like to replace the innerHTML of a  of a particular class with the innerHTML of a different elemets innerHTML based on that other elements class. I'm trying to dynamically match a header to the selected menu item.</p>
  
  <p>Basically I want to take the innerHTML of whatever has the class "categorySidebarLabelSelected".</p>
  
  <pre><code>&lt;a class="categorySidebarLabelSelected"&gt;Guest Relations&lt;/a&gt;
  </code></pre>
  
  <p>And replace the "Start a document" with "Guest Relations" based on the class "areaTitle".</p>
  
  <pre><code>&lt;div class="areaTitle"&gt;Start a document&lt;/div&gt;
  </code></pre>
  
  <p>so the results would be:</p>
  
  <pre><code>&lt;div class="areaTitle"&gt;Guest Relations&lt;/div&gt;
  </code></pre>