摘要： 1.清除元素的浮动属性p：元素A有float属性，其它元素会受其影响s：在其父元素添加clearfix属性，它的CSS样式为：.clearfix:after { content: " "; /* Older browser do not support empty content */ visibility: hidden; display: block; height: 0; clear: both;}2.纯css实现下拉图标border-top:4px solid;border-right:4px solid transpant;border-left:4px soli 阅读全文