chromium/third_party/blink/web_tests/external/wpt/html/browsers/windows/nested-browsing-contexts/resources/frameElement-window-post.html

<!DOCTYPE html>
<meta charset="utf-8"/>
<title>Testcase 3: frameElement attribute must return null if the container\'s document does not have the same effective script origin</title>
<script>
window.addEventListener("message", function (event) {
  try {
    var result = "window.frameElement = " + window.frameElement;
  } catch (e) {
    result = e.message;
  }
  event.source.postMessage(JSON.stringify({name: "testcase3", result: result}),
                           "*");
}, false);
</script>