:required

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摘要

:required  CSS 伪类 表示任意设置了required属性的<input><select>, 或 <textarea>元素。 这个伪类对于高亮显示在提交表单之前必须具有有效数据的字段非常有用。

注意::optional伪类选中'可选的'表单字段。

语法

:required

例子

查看示例 :invalid .

规范

Specification Status Comment
HTML Living Standard
:required
Living Standard No change.
HTML5
:required
Recommendation Defines the semantic regarding HTML and constraint validation.
Selectors Level 4
:required
Working Draft No change.
CSS Basic User Interface Module Level 3
:required
Recommendation Defines the pseudo-class, but not the associated semantic.

浏览器兼容

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!
Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 10.0 4.0 (2) 10 10.0 5.0
Feature Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? 4.0 (2) 未实现 10.0 5.0

参见