<style>
  @font-face {
      font-family: "AhemTest";
      src: url(http://127.0.0.1:8080/css/resources/cors-ahem.php);
  }
  p { font-family: AhemTest; }
</style>
<p>Yay!</p>
<script>
window.onload = function() {
    if (window.opener)
        window.opener.postMessage('done', '*');
};
</script>