title: JSDOM returns an empty element
body: <p>Here is the snippet </p>
  
  <pre><code>let thtml = "&lt;html&gt;&lt;body&gt;&lt;div id=app&gt;&lt;div id=viewer&gt;&lt;/div&gt;&lt;/div&gt;&lt;/body&gt;&lt;/html&gt;"
  jsdom.env({
    html: thtml ,       
    done: function(err: any, window: any) {
     console.log(window.document.getElementById("viewer")); 
    }
  });
  </code></pre>
  
  <p>Here <code>window.document.getElementById("viewer")</code> returns an empty <code>HTMLDivElement</code>. 
  In Chrome, I got div <code>id="viewer"</code> the expectation is it should return the same div element.</p>
  
  <p>Is it a bug or am I missing something here?</p>