<!DOCTYPE HTML> <html class="reftest-wait"> <head> <style> body { width: 1500px; overflow: hidden; } div#bottom { position: fixed; left: 0; top: 0; height: 200px; width: 200px; background: green; } </style> </head> <body> <div id="bottom"></div> <div style="width:600px; height:100px; background:pink;"></div> <script> document.documentElement.scrollLeft = 200; function doTest() { document.documentElement.removeAttribute("class"); document.documentElement.scrollLeft = 0; } window.addEventListener("MozReftestInvalidate", doTest, false); </script> </body> </html>