Error parsing HTML as JSON

[doggy8088]

Here is a sample page: http://output.jsbin.com/dapefoh

  12345
  
  1 2 3 4 5
  
  <ol>
    <li>123</li>
    <li>321</li>
    <li>123</li>
    <li>321</li>
    <li>123</li>
  </ol>
  
  <h1>OK</h1>

If JSON Viewer been enabled, the browser will show different layout.

Expected:

Actual: