<!DOCTYPE html>
<html class="reftest-wait">
<head>
<style>
#d1 {
  width: 250px;
  height: 200px;
  margin: 200px;
  transform: translateY(10px);
}
#d1.hidden {
  transform: translateY(20px);
}
#d2 {
  background-color: yellow;
  position: relative;
  width: 100px;
  height: 100px;
  left: 0;
}
.hidden > #d2 {
  left: -100px;
}
</style>
</head>
<body>
<div id="d1">
  <div id="d2"></div>
</div>
<script>
window.addEventListener("MozReftestInvalidate", function() {
  d1.classList.toggle("hidden");
  document.documentElement.removeAttribute("class");
});
</script>
</body>
</html>