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本文档使用
php.cn手册 发布
文字
语法：
E:after/E::after { sRules }
说明：
设置在对象后（依据对象树的逻辑结构）发生的内容。用来和content属性一起使用，并且必须定义content属性
CSS3将伪对象选择符(Pseudo-Element Selectors)前面的单个冒号(:)修改为双冒号(::)用以区别伪类选择符(Pseudo-Classes Selectors)，但以前的写法仍然有效。
即E:after可转化为E::after
兼容性：
| Selector | IE | Firefox | Chrome | Safari | Opera | iOS Safari | Android Browser | Android Chrome |
|---|---|---|---|---|---|---|---|---|
| Basic Support | 6.0-7.0 | 2.0-3.0 #2 | 4.0+ | 3.1+ | 15.0+ | 3.2+ | 2.1+ | 18.0+ |
| 8.0+ | 3.5+ | |||||||
| ::after | 6.0-7.0 | 2.0-3.0 #2 | ||||||
| 8.0 #1 | 3.5+ | |||||||
| 9.0+ | ||||||||
| 应用动画 | 6.0-9.0 | 2.0-3.5 | 4.0-25.0 | 3.1-6.0 | 15.0+ | 3.2-6.1 | 2.1-3.0 | 18.0-25.0 |
| 10.0+ #3 | 4.0+ | 26.0+ | 6.1+ | 7.0+ | 4.0+ | 26.0+ |
本质上并不支持伪元素的双冒号(::)写法，而是忽略掉了其中的一个冒号，仍以单冒号来解析，所以等同变相支持了E::after。
不支持设置属性position, float, list-style-*和一些display值，Firefox3.5开始取消这些限制。
IE10在使用伪元素动画有一个问题：
例如：
.test:hover {} .test:hover::after { /* 这时animation和transition才生效 */ }需要使用一个空的:hover来激活
示例：
实例
<!DOCTYPE html>
<html lang="zh-cmn-Hans">
<head>
<meta charset="utf-8" />
<title>E::after_CSS参考手册_web前端开发参考手册系列</title>
<meta name="author" content="Joy Du(飘零雾雨), dooyoe@gmail.com, www.doyoe.com" />
<style>
p{position:relative;color:#f00;font-size:14px;font-size:0\9;*font-size:14px;}
p:after{position:absolute;left:0;background:#fff;color:#000;content:"如果你的能看到这段文字，说明你的浏览器只支持E:after";font-size:14px;}
p::after{position:absolute;left:0;background:#fff;color:#000;content:"如果你的能看到这段文字，说明你的浏览器支持E:after和E::after";font-size:14px;}
</style>
</head>
<body>
<p>Sorry, 你的浏览器不支持E:after和E::after</p>
</body>
</html>
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