清除浮动的4种方法
1.额外标签法: < ! DOCTYPE html > < html lang = "en" > < head > < meta charset = "UTF-8" > < meta name = "viewport" content = "width=device-width, initial-scale=1.0" > < meta http-equiv = "X-UA-Compatible" content = "ie=edge" > < title > 额外标签法 < /title > < style > .box { width:1000px ; margin: 0 auto ; border: 1px solid blue ; } .damao { float: left ; width: 300px ; height: 200px ; background-color: purple ; } .ermao { float: left ; width: 200px ; height: 200px ; background-color: pink ; } .footer { height: 200px ; background-color: black ; } /* 清除浮动 */ .clear { clear: both ; } < /style > < /head >