HTTP/1.1 200 OK
Server: Apache
Date: Wed, 09 Dec 2015 03:29:14 GMT
Content-Type: text/html; charset=utf-8
Connection: keep-alive

<html>
  <head>
    <title>Test</title>
  </head>
  <body class="h-entry">
    <div class="e-content">
      <p>This is a nice video!</p>
      <iframe width="560" height="315" src="https://www.youtube.com/embed/y9FSPcmybT8" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
      <p>This is a not a nice video!</p>
      <iframe width="580" height="345" src="https://attack-domain.com" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
    </div>
  </body>
</html>