title: get available height of browser window from within iframes
body: <p>I have the following structure of my website:</p>
  
  <pre><code>&lt;html&gt;
    &lt;iframe&gt;
      &lt;iframe&gt;
      &lt;/iframe&gt;
    &lt;/iframe&gt;
  &lt;html&gt;
  </code></pre>
  
  <p>I am prgramming the part of the most inner <code>iframe</code>. Now I want to determine the available <code>height</code> of the browser window (starting under the <code>menubar</code> and ending before possible <code>toolbar</code>s). </p>
  
  <p>I have <strong>IE9</strong> and tried somthing like: </p>
  
  <pre><code>window.innerHeight
  </code></pre>
  
  <p><strong>(result undefined) and</strong> </p>
  
  <pre><code>window.parent.document.body.clientHeight 
  </code></pre>
  
  <p><strong>(not the height I expected)</strong>. </p>
  
  <p>How do I get the <code>height</code>? Thanx in advance.</p>