title: Inline iframe does not get loaded
body: <p>If I create an HTML file with an inline iframe like this</p>
  
  <pre><code>&lt;body&gt;
      &lt;iframe&gt;
          &lt;html&gt;
              &lt;body&gt;
                  Hello World!!
              &lt;/body&gt;
          &lt;/html&gt;
      &lt;/iframe&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p>and open the page in browser, nothing gets printed.
  But if I specify a <code>&lt;iframe src="test.php"&gt;</code> attribute, with <code>test.php</code> having the same code,</p>
  
  <pre><code>&lt;html&gt;
      &lt;body&gt;
          Hello World!!
      &lt;/body&gt;
  &lt;/html&gt; 
  </code></pre>
  
  <p>as the inline iframe, I get "hello world" printed... why is that? Is an inline iframe not legal?</p>