<!DOCTYPE html>
<html>
<head>
  <meta charset=utf-8>
  <title>&lt;hr&gt;</title>
</head>
<body>
  <!-- is not structured inline -->
  <p>
    <ul>
      <li>
        <hr>
      </li>
    </ul>
  </p>

  <!-- is not strictly inline -->
  <p><dfn>text
    <hr>
  </dfn></p>

  <!-- must be empty -->
  <hr>
    <p>p1</p>
  
  <hr><em>text</em>
</body>
</html>