HarryM - 7:14 pm on Sep 29, 2007 (gmt 0)

<div class="spacer"></div>

If I remember correctly, some older browsers don't like empty divs.

It may not be neccessary today, but I always use:

<div class="clear">&nbsp;</div>

.clear{
height:0;
font-size:0;
line-height:0;
clear:both;
}