<!DOCTYPE html>
<html>
<head>
  <script type="text/javascript">
    function doTest()
    {
      document.getSelection().selectAllChildren(document.getElementById("text"));
      var editor = document.getElementById("editor");
      var editorBody = editor.contentDocument.body;
      editor.contentDocument.getSelection().selectAllChildren(editorBody);
      editor.focus();
      editor.blur();
    }
  </script>
</head>
<body>
<p id="text">normal text</p>
<iframe id="editor" onload="doTest();"
  src="data:text/html,<script>document.designMode='on';</script><body>editable text</body>"></iframe>
</body>
</html>