<!DOCTYPE HTML> <html class="reftest-wait"> <head> <style> html { background:white; } #parent { position: absolute; top: 100.8px; transform: scale(1.1232,1.1232); transform: scale(1.1232,1.1232); } #b1 { position: absolute; width: 100px; height: 109px; background: #c00; transform: translate(100px,100px); transform: translate(100px,100px); } #b2 { position: absolute; top: 0; left: 0; width: 100px; height: 100px; background: white; transform: translate(400px,200px); transform: translate(400px,200px); } #b2.done { transform: translate(400px,0); transform: translate(400px,0); } </style> </head> <body> <div id="parent"> <div id="b1"></div> <div id="b2"></div> </div> <script> function doTest() { document.getElementById('b2').setAttribute("class", "done"); document.documentElement.removeAttribute("class"); } window.addEventListener("MozReftestInvalidate", doTest); </script> </body> </html>