問題描述

CSS 2.1 :after 和 CSS 3 ::after 偽選擇器(除了 ::after 舊版瀏覽器不支持)?是否有任何實際理由使用新規范?

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?

推薦答案

這是偽類 vs 偽元素的區別.

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

::first-line、::first-letter、::before 和 ::after 除外code>(已經存在了一段時間，如果您需要 IE8 支持，可以與單冒號一起使用)，偽元素 需要雙冒號.

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 選擇實際元素本身，可以使用 :first-child 或 :nth-of-type(n) 進行例如，選擇 div 中的第一個或特定 <p>.
(還有實際元素的狀態，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 以元素的子部分為目標，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.

實際上，更好的描述在這里:http://bricss.net/post/10768584657/know-your-lingo-pseudo-class-vs-pseudo-element
也在這里: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/

這篇關于:after 與 ::after的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！