.fix{
	*zoom:1; //JUST FOR IE
}
.fix:after{
	display:block;
	content:"$";
	height:0;
	clear:both;
	overflow:hidden;
	visibility:hidden;
}

使用方法:

<div class="fix">
	<div class="left">
		float:left
	</div>
	<div class="right">
		float:right
	</div>
</div>