<html xmlns="http://www.w3.org/1999/xhtml"> <head> <style id="ss" type="text/css"> #o { height: 65px; } </style> <script type="text/javascript"> function boom() { document.getElementById("ss").disabled = true; document.documentElement.offsetHeight; document.getElementById("ss").disabled = false; } </script> </head> <body onload="boom();"> <div style="-moz-column-width: 0;"> <colgroup></colgroup> <div> <div id="o" style="float: left;"></div> <div style="clear: both;">A B<div style="float: left;"></div></div> </div> </div> </body> </html>