<!DOCTYPE html>
<html>
<head>
<script>

function boom()
{
  var otherDoc = document.implementation.createDocument('', '', null);
  var input = otherDoc.createElementNS("http://www.w3.org/1999/xhtml", "input");
  var form = otherDoc.createElementNS("http://www.w3.org/1999/xhtml", "form");
  input.setAttributeNS(null, "form", "x");
  form.setAttributeNS(null, "id", "x");
  input.appendChild(form);
  otherDoc.appendChild(input);
}

</script>
</head>
<body onload="boom();"></body>
</html>
