清除浮动

1.<div style="clear:both"></div>

2.:after{ content:""; clear:both;disblock:block; height:0;visibility:hidden;},他的父标签{zoom:1;}

3.:before,:after{content:""; display:table;} :after{clear:both;} ,他的父标签{zoom:1;}

4.给浮动元素添加overflow:auto样式；

.clear{zoom:1;}
.clear:after{ content:""; clear:both;disblock:block; height:0;visibility:hidden;}