Float特徵:html
1.塊在一排顯示佈局
2.支持內聯寬度spa
3.默認內容支撐寬度htm
4.脫離文檔流blog
5.提高層級半層文檔
Float產生的影響:it
float有脫離文檔流的特性使其與父級不在同一文檔流,從而影響佈局。class
例如如下代碼:item沒有撐起box的高度擴展
<head>
<style> .box{ border: 2px solid #00008B; } .item{ background-color: red; width: 100px; height: 100px; float: left; } </style> </head> <body> <div class="box"> <div class="item"></div> </div> </body>
清除Float方法:meta
1.加高度(擴展性很差)
<head> <meta charset="UTF-8"> <title></title> <style> .box{ border: 2px solid #00008B; height: 100px; } .item{ background-color: red; width: 100px; height: 100px; float: left; } </style> </head> <body> <div class="box"> <div class="item"></div> </div> </body>
2.父級浮動(頁面中全部元素都加浮動,會影響margin左右自動失效)
<head> <meta charset="UTF-8"> <title></title> <style> .box{ border: 2px solid #00008B; float: left; } .item{ background-color: red; width: 100px; height: 100px; float: left; } </style> </head> <body> <div class="box"> <div class="item"></div> </div> </body>
3.inline-block(margin左右auto失效)
<head> <meta charset="UTF-8"> <title></title> <style> .box{ border: 2px solid #00008B; display: inline-block; } .item{ background-color: red; width: 100px; height: 100px; float: left; } </style> </head> <body> <div class="box"> <div class="item"></div> </div> </body>
4.空標籤(ie6最小高度16px)
<head> <meta charset="UTF-8"> <title></title> <style> .fix{ clear: both; } .box{ border: 2px solid #00008B; } .item{ background-color: red; width: 100px; height: 100px; float: left; } </style> </head> <body> <div class="box"> <div class="item"></div> <div class="fix"></div> </div> </body>
5.br
<head> <meta charset="UTF-8"> <title></title> <style> .box{ border: 2px solid #00008B; } .item{ background-color: red; width: 100px; height: 100px; float: left; } </style> </head> <body> <div class="box"> <div class="item"></div> <br clear="all"/> </div> </body>
6.after僞類(content屬性)
<head> <meta charset="UTF-8"> <title></title> <style> .box:after{ content: " "; clear: both; display: block; } .box{ border: 2px solid #00008B; } .item{ background-color: red; width: 100px; height: 100px; float: left; } </style> </head> <body> <div class="box"> <div class="item"></div> </div> </body>
7.overflow(hidden | scroll等)
<head> <meta charset="UTF-8"> <title></title> <style> .box{ border: 2px solid #00008B; overflow: hidden; } .item{ background-color: red; width: 100px; height: 100px; float: left; } </style> </head> <body> <div class="box"> <div class="item"></div> </div> </body>