清除浮动：clearfix

传统方案

在需要清除浮动的地方加个div.clear或者br.clear

.clear{    clear: both;    height: 0;    overflow: hidden;}

缺点：
改变了html的结构，添加了个div

---

最优浮动解决方案

.clearfix:after {    content: ".";    display: block;    height: 0;    clear: both;    visibility: hidden;}.clearfix {    *+height:1%;}

or

.clearfix:after {    visibility: hidden;    display: block;    content: " ";    clear: both;}.clearfix {    zoom:1;}

---

最暴力的浮动闭合方式

.clearfix {    overflow: auto;    _height:1%;}