<!DOCTYPE html>
<html class="reftest-wait" style="height: 100%">
  <head>
    <script>
      function doIt() {
        var d = document.createElement("div");
        d.setAttribute("style",
                       "position: absolute; left: 0; right: 0; top: 0; " +
                       "bottom: 0; background: green");
        document.getElementById("x").appendChild(d);
        document.documentElement.removeAttribute("class");
      }
      window.addEventListener("MozReftestInvalidate", doIt);
    </script>
  </head>
  <body style="height: 100%">
    <fieldset id="x" style="position: relative; display: table; width: 50%;
                            height: 50%; top: 25%; left: 25%">
    </fieldset>
  </body>
</html>