<html class="reftest-wait"> <head> <script> function boom() { document.body.offsetHeight; var lastdiv = document.getElementById("last"); var parent = lastdiv.parentNode; for (var i = 2; i <= 4; i++) { var newdiv = document.createElement("div"); newdiv.appendChild(document.createTextNode(i)); parent.insertBefore(newdiv, lastdiv); } document.body.offsetHeight; document.documentElement.className = ""; } </script> </head> <body onload="boom();"> <div>1</div> <div id="last">5</div> </body> </html>