<!DOCTYPE html>
<html>
  <head>
    <script src="util.js"></script>
    <script>
window.onload = function() {
  document.head.appendChild(build_rule("caption > div, caption > span", 20000, "{ color: blue; } "));
  let dom = build_dom(5000, "div");

  flush_layout();
  perf_start();
  document.body.appendChild(dom);
  flush_style(dom);
  perf_finish();
};
    </script>
  </head>
  <body>
  </body>
</html>
