<!DOCTYPE HTML> <html><head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <style type="text/css"> .p { marker: url('#c'); } </style> <script type="text/javascript"> function boom() { document.getElementById("a").setAttribute("class", "p"); document.documentElement.offsetHeight; document.getElementById("b").setAttribute("id", "c"); } </script> </head><body onload="boom();"><div class="p" id="a">C</div><div id="c"></div></body></html>