爲父元素或者元素本身添加樣式
.clearfix:after{
content:".";
display:block;
height:0;
visibility:hidden;
clear:both;
}
爲父元素或者元素本身添加樣式
.clearfix:after{
content:".";
display:block;
height:0;
visibility:hidden;
clear:both;
}