css清除浮动方法

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

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

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

.clearfix{overflow:hidden;_zoom:1;}