<html class="reftest-wait"> <head> <style> div#blurred { box-shadow: 0 0 50px 0 #000; position: absolute; width: 100px; height: 100px; top: 30px; left: 30px; border-radius: 40px; } </style> </head> <body> <div id="blurred"></div> <script> function doTest() { var div = document.getElementById("blurred"); div.style.left = '60px'; document.documentElement.removeAttribute("class"); } document.addEventListener("MozReftestInvalidate", doTest, false); </script> </body> </html>