<!DOCTYPE html>
<html>
<head>
  <meta charset=utf-8>
  <title>&lt;iframe&gt;</title>
</head>
<body>
  <!-- is structured inline -->
  <p><iframe
      name="frame1"
      src="uri"
      width="2"
      height="90"
      frameborder="0"
      scrolling="yes"
      class="class"
      lang="en"></iframe></p>

  <!-- is strictly inline -->
  <p><dfn><iframe
      name="frame1"
      src="uri"
      width="2"
      height="90"
      frameborder="1"
      scrolling="no"
      class="class"
      lang="en"></iframe></dfn></p>

  <!-- is block -->
  <iframe
      name="frame1"
      src="uri"
      width="2"
      height="90"
      frameborder="0"
      scrolling="auto"
      class="class"
      lang="en"></iframe>

  <!-- can contain inline while in inline context -->
  <p>paragraph
    <iframe>
        <em>some</em> <ul><li>inline</li></ul> content
    </iframe>
  </p>
  <!-- can contain strictly inline while in strictly inline context -->
  <p><dfn>strictly inline
    <iframe>
        <em>text</em>
    </iframe>
  </dfn></p>

  <!-- can contain blocks while in block context -->
  <iframe>
    <p>text</p>
  </iframe>

  <!-- can contain interactive if ancestor does not forbid it -->
  <p>paragraph
    <iframe>
      <a>link</a>
    </iframe>
  </p>
  <p><dfn>strictly inline
    <iframe>
      <a>link</a>
    </iframe>
  </dfn></p>
  <iframe>
    <p><a>link</a></p>
  </iframe>
</body>
</html>
