:after 与 ::after

:after vs. ::after(:after 与 ::after)

问题描述

CSS 2.1 :after 和 CSS 3 ::after 伪选择器(除了 ::after 旧版浏览器不支持)?是否有任何实际理由使用新规范?

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

这是伪类 vs 伪元素的区别.

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

::first-line、::first-letter、::before 和 ::after 除外code>(已经存在了一段时间，如果您需要 IE8 支持，可以与单冒号一起使用)，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.

Pseudo-classes 选择实际元素本身，可以使用 :first-child 或 :nth-of-type(n) 进行例如，选择 div 中的第一个或特定 <p>.
(还有实际元素的状态，例如 :hover 和 :focus.)

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.)

Pseudo-elements 以元素的子部分为目标，例如 ::first-line 或 ::first-letter，本身不是元素.

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

实际上，更好的描述在这里:http://bricss.net/post/10768584657/know-your-lingo-pseudo-class-vs-pseudo-element
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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