<!DOCTYPE HTML> <html class="reftest-wait"> <head> <style> body { font-family: sans-serif; } </style> <script type="text/javascript"> var loopCount = 0; var pause = 10; // smaller values make the bug more likely to occur var src = "data:text/html,iframe 1 <iframe width='100' height='100' src='data:text/html,iframe 2'>"; var start = new Date(); function ap() { document.getElementById("div").style.position = "absolute"; setTimeout(bp, pause); } function bp() { document.getElementById("div").style.position = ""; setTimeout(cp, pause); } function cp() { document.getElementById("iframe").setAttribute("src", src); setTimeout(nextIteration, pause); } function nextIteration() { var now = new Date(); loopCount++; if (loopCount < 20 && now - start < 5000) { ap(); } else { document.body.textContent = "Done"; document.documentElement.className = ''; } } </script> </head> <body onload="ap();"><div id="div"><iframe id="iframe"></iframe></div></body> </html>