w3c / w3c/csswg-drafts

[cssom] Should getComputedStyle() support non-standard pseudo-elements?

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Description

https://drafts.csswg.org/cssom/#dom-window-getcomputedstyle

See https://github.com/w3c/csswg-drafts/pull/3968#issuecomment-496033399

Why does getComputedStyle() support any pseudo-element? Previously it only supported ::before and ::after.

This is an issue for appearance because UAs can support non-standard values for non-standard pseudo-elements. (Though css-ui could require auto to be used instead.)

Do we want such pseudo-elements to be available in author CSS? Do we want to support them in getComputedStyle()?

cc @frivoal @fantasai @FremyCompany

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First steps

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  3. Fork the repository and make your change on a branch.
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Research direction

Read the CSSOM getComputedStyle() definition and the CSSWG pull request 3968 comment linked in the issue. Resolve whether non-standard pseudo-elements should be exposed to author CSS and supported by getComputedStyle(), including the appearance/auto question; done means the specification's intended behavior is decided and reflected in the relevant draft.

Written by the indexing model from the issue text.

Assessment

Tech stack
css
Domain
frontend, web-dev
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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