<!DOCTYPE HTML> <html class="reftest-wait"> <head> <style> body { margin: 0; display: -moz-box; -moz-box-orient: horizontal; width: 400px; } canvas { -moz-box-flex: 1; opacity: 0.999; border: 1px solid black; } .censor { position: absolute; width: 1px; height: 1px; background: cyan; } </style> </head> <body> <canvas id="c" width="100" height="100"></canvas> <script> var ctx = document.getElementById("c").getContext('2d'); ctx.fillStyle = "lime"; ctx.fillRect(0, 0, 100, 100); function doTest() { document.body.style.width = "502px"; document.documentElement.removeAttribute("class"); } window.addEventListener("MozReftestInvalidate", doTest, false); </script> <div class="censor" style="left:0; top:0;"></div> <div class="censor" style="left:501px; top:0;"></div> <div class="censor" style="left:0; top:101px;"></div> <div class="censor" style="left:501px; top:101px;"></div> </body> </html>