<!DOCTYPE html> <html class="reftest-wait"> <head> <script> window.addEventListener("MozReftestInvalidate", function() { var b = document.createElement("body"); b.style.background = "green"; document.documentElement.appendChild(b); document.documentElement.className = ""; }, false); </script> </head> <body style="background: red"> <script> document.documentElement.removeChild(document.body); </script> </body> </html>