<!DOCTYPE HTML> <html class="reftest-wait"> <body> <div id="d1" style="width:100px; height:100px; background:lime;"></div> <div id="d2" style="width:100px; height:100px; background:cyan; opacity:0.8;">Hello Kitty</div> <script> var d1 = document.getElementById("d1"); var d2 = document.getElementById("d2"); document.body.offsetTop; d1.style.height = "150px"; d2.style.opacity = "0.6"; function doTest() { d1.style.height = "200px"; d2.style.opacity = 0.4; document.documentElement.removeAttribute("class"); } window.addEventListener("MozReftestInvalidate", doTest, false); </script> </body> </html>