:optional

摘要

:optional CSS 伪类 表示任意没有required属性的 <input><select> 或  <textarea> 元素使用它。

/* Selects any optional <input> */
input:optional {
  border: 1px dashed black;
}

它允许表单容易的展示可选字段并且渲染其外观。

注:为必填字段设置外观,请使用 :required伪类。

语法

:optional

例子

查看:invalid 示例。

规范

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

浏览器兼容性

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! (en-US)

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