清除浮动

clear

.box{

width:100px;

height:100px;

background-color:red;

clear:left;

}

清除左浮动

.box{

width:100px;

height:100px;

background-color:red;

clear:right;

}

清除右浮动

.clearfix:after

.clearfix:after{

content:' ';display:hidden;

clear:both;

}