<!DOCTYPE html> <html class="reftest-wait"> <body> <canvas width="100" height="100" id="c"></canvas> <script> var c = document.getElementById("c"); var ctx = c.getContext("2d"); ctx.fillStyle = "red"; ctx.fillRect(0,0,100,100); function finishTest() { c.width = 200; c.height = 200; ctx.fillStyle = "lime"; ctx.fillRect(0,0,200,200); document.documentElement.removeAttribute("class"); } window.addEventListener("MozReftestInvalidate", finishTest, false); </script> </body> </html>