title: $(document.body).height() returns the same value as $(window).height()
body: <p>my basic structure was like this:</p>
  
  <pre><code>&lt;body&gt;
      &lt;div id="controlBar"&gt;&lt;/div&gt;
      &lt;div id="placeholder"&gt;&lt;/div&gt;
      &lt;div id="pageHeader"&gt;
        &lt;nav&gt;&lt;ul&gt;&lt;li&gt;&lt;li&gt;&lt;/ul&gt;&lt;/nav&gt;
      &lt;/div&gt;
      &lt;section id="pageContent"&gt;&lt;/section&gt;
      &lt;footer id="pageFooter"&gt;&lt;/footer&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p>where <code>#controlBar</code> has a fixed position and <code>#placeholder</code> has the same height as <code>#controlBar</code>.  The combine height inside the body was about 400px.</p>
  
  <p>I'm trying to get the height of the body using <code>$(document.body).height()</code>, but the value returned was the same as <code>$(window).height()</code>, which is over 900px. I also tried <code>$(document).height()</code>, but still same result.</p>