.box{ width:300px;margin:0 auto;border:10px solide #000;}

.p{ width:200px;height:200px;background:red;float:left;}

. clear{ height:0px;font-size:0;clear:both;overflow : caché;}

Exemple2 :Utiliser

.box{ width:300px;margin:0 auto;border:10px solid #000;}

.p{ width:200px;height:200px;background:red;float:left;}

示例3 ：伪类对象::after+zoom:1(推荐使用)

< ;/p>

.box{margin:0 auto;border:10px solide #000;}

.p{ width:200px;height:200px;background:red;float:left;}

. clear{zoom:1;}

.clear:after{display:block;clear:both;content:"";visibility:hidden;height:0}