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: