<head>
  <meta charset="utf-8"/>
  <title>Test</title>
</head>
<body>
<div xmlns:ex="http://example.org/">
  <p property="ex:test1">Test 1 <p property="ex:test2">Test 2</p>
  </p> <!-- (this tag is a parse error in HTML5) -->
</div>

</body>
