CSS :open pseudo-class

[josepharhar]

こんにちは TAG-さん!

I'm requesting a TAG review of CSS :open pseudo-class.

This pseudo-class applies to HTML elements which have an "open" state. For <details>, this is when the element is expanded. For <dialog>, this is when the element is showing. For <select>, this is when the picker is showing.

• Explainer¹: none
• Specification: https://drafts.csswg.org/selectors-4/#open-state
• WPT Tests: https://wpt.fyi/results/css/selectors/open-closed-pseudo.html
• User research: none
• Security and Privacy self-review²:
• GitHub repo: https://github.com/w3c/csswg-drafts/
• Primary contacts:
  • Joey Arhar @josepharhar Google
• Organization/project driving the specification: Google
• Multi-stakeholder support³:
  • Chromium comments: yes
  • Mozilla comments: :open and :closed pseudo-classes mozilla/standards-positions#1085
  • WebKit comments: :open and :closed pseudo-classes WebKit/standards-positions#413
• Status/issue trackers for implementations⁴: https://chromestatus.com/feature/5085419215781888

Further details:

• I have reviewed the TAG's Web Platform Design Principles
• Relevant time constraints or deadlines:
• The group where the work on this specification is currently being done: CSSWG
• The group where standardization of this work is intended to be done (if different from the current group):
• Major unresolved issues with or opposition to this specification: [selectors-4] Should we have :open and :closed? w3c/csswg-drafts#11039
• This work is being funded by: Google

[plinss]

We looked at this in a breakout today and don't see any issues. Closing as satisfied.

We did note w3c/csswg-drafts#11039 and agree that if :not(:open) is equivalent to :closed then :closed isn't necessary and probably should be removed. However if it's possible that an element could be in a state that's neither open or closed, then they're not exactly equivalent and :closed has a purpose.

Thanks for flying TAG.