:optional
摘要
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
BCD tables only load in the browser