<!DOCTYPE html>
<style>
.x { color: yellow; }
</style>
<script src="util.js"></script>
<script>
function set_class(n) {
  n.className = "x";
  n = n.firstChild;
  while (n) {
    set_class(n);
    n = n.nextSibling;
  }
}
window.onload = function() {
  let root = build_dom(50000, "div");
  document.body.appendChild(root);
  flush_layout(root);
  perf_start();
  set_class(root);
  flush_style(root);
  perf_finish();
};
</script>
<body></body>
