<!DOCTYPE HTML>
<html class="reftest-wait">
<body>
<iframe id="f" src="data:text/html,<div style='height:1000px; background:yellow'>" style="overflow:hidden"></iframe>
<script>
function doTest() {
  var f = document.getElementById("f");
  f.style.overflow = "visible";
  document.documentElement.removeAttribute("class");
}
window.addEventListener("MozReftestInvalidate", doTest, false);
</script>
</body>
</html>