<!DOCTYPE HTML> <html class="reftest-wait"> <head> <style> #d2 { opacity:0; transition:all 0.2s; position:absolute; } #d2.active { opacity:1; } #image { position:fixed; width:100%; height:100%; background:blue; left:0; top:0; } </style> </head> <body> <div id="d2" class="active"> <div id="image"></div> <h2>ABCDEFG</h2> </div> <script> function doTest() { d2.addEventListener("transitionend", function() { document.documentElement.removeAttribute("class"); }); d2.classList.toggle("active"); } window.addEventListener("MozReftestInvalidate", doTest); </script> </body> </html>