：after vs. :: after [英] :after vs. ::after

问题描述

CSS 2.1 ：之后和CSS 3 :: after 伪选择器之间是否有任何功能差异（旧的浏览器不支持 :: after 之后）？

Is there any functional difference between the CSS 2.1 :after and the CSS 3 ::after pseudo-selectors (other than ::after not being supported in older browsers)? Is there any practical reason to use the newer specification?

推荐答案

这是伪 class vs pseudo- 元素。

It's pseudo-class vs pseudo-element distinction.

除了 ::一行， :: first-letter ， :: before 和 :: after 已经有一段时间了，如果您需要IE8支持，可以使用单冒号），伪元素 需要双冒号。

Except for ::first-line, ::first-letter, ::before and ::after (which have been around a little while and can be used with single colons if you require IE8 support), pseudo-elements require double colons.

伪类自己选择实际元素，您可以使用：first-child 或：

Pseudo-classes select actual elements themselves, you can use :first-child or :nth-of-type(n) for selecting the first or specific <p>'s in a div, for example.
(And also states of actual elements like :hover and :focus.)

伪元素定位 :: first-line 或 :: first-letter ，这些东西本身就不是元素。

Pseudo-elements target a sub-part of an element like ::first-line or ::first-letter, things that aren't elements in their own right.

其实，这里更好的描述： http://bricss.net/post/10768584657/know-your-lingo-pseudo-class-vs-pseudo-element < a>

也在这里： http://www.evotech.net/blog/2007/05/after-v-after-what-is-double-colon-notation/

Actually, better description here: http://bricss.net/post/10768584657/know-your-lingo-pseudo-class-vs-pseudo-element
Also here: http://www.evotech.net/blog/2007/05/after-v-after-what-is-double-colon-notation/

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