<!DOCTYPE html>
<html>
  <head>
    <script>
function appendScript(doc) {
  var s = doc.createElement("script");
  s.textContent = "document.write('executed'); document.close()";
  doc.body.appendChild(s);
}
    </script>
  </head>
  <body onload="appendScript(window.document)">
  </body>
</html>