chromium/third_party/blink/web_tests/external/wpt/html/semantics/scripting-1/the-script-element/execution-timing/pages/helloworld-postMessage.html

<!DOCTYPE html>
<html><head>
  <title> TC component </title>
</head>
<body>

  <p>This page should appear in popup or frame</p>

  <script type="text/javascript">
  var target = opener || top;
  var id = location.search?' '+location.search.substring(1) : '';
  target.log('frame/popup script'+id);
  window.onload=function(){
    target.log('load event inside frame/popup script'+id);
    target.postMessage('msg evt frame/popup script'+id, '*');
  }
  </script>

</body></html>