<style>
.clearfix:before, .clearfix:after { content:""; display:table; }
.clearfix:after { clear: both; }
.clearfix { zoom: 1; }
</style>

<ul class="clearfix">
<li style="float:left">浮动元素</li>
<li style="float:left">浮动元素</li>
</ul>
<div>后面内容</div>