Intent to Ship: CSS spelling and grammar features

Stephen Chenney

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Oct 30, 2023, 8:37:34 PM10/30/23

to blink-dev

The CSS Spelling and Grammar feature has been active behind experimental web platform features since M89! There are no open bugs. I would like to turn it on at last for M120.

Summary

CSS highlight pseudo-elements for styling text that the UA has flagged as misspelled or grammatically incorrect, and line decorations exposing the UA’s default decorations for spelling and grammar errors. These features allow authors to choose more legible colors for the default spelling and grammar errors, highlight misspelled words with background colors or other decorations, and implement custom spell checking with almost-native appearance.

Blink component

Blink>CSS

Search tags

spelling-error, grammar-error, highlight pseudos

TAG review

None

TAG review status

Not applicable

Risks

Interoperability and Compatibility

https://developer.mozilla.org/en-US/docs/Web/CSS/::spelling-error https://developer.mozilla.org/en-US/docs/Web/CSS/::grammar-error

Gecko: No signal (https://github.com/mozilla/standards-positions/issues/470)

WebKit: In development (https://lists.webkit.org/pipermail/webkit-dev/2021-January/031660.html) WebKit has an old WIP patch from 2018 at https://webkit.org/b/175784 CSS Working group minutes imply Safari is planning an implementation: https://github.com/w3c/csswg-drafts/issues/7522

Web developers: Positive (https://dev.to/lampewebdev/css-pseudo-elements-classes-you-have-never-heard-of-30hl#the-grammarerror-and-spellingerror-pseudoelement)

Other signals: The spec for the text-decoration-line: spelling-error/grammar-error is https://drafts.csswg.org/css-text-decor-4/#text-decoration-line-property

Ergonomics

The new pseudo-elements depend on the new ‘text-decoration-line’ values for UA stylesheet support. They are highlight pseudos, which should pose minimal performance risk due to the limited set of CSS properties they allow: <https://drafts.csswg.org/css-pseudo-4/#highlight-styling>

Security

See, for example, https://github.com/w3c/csswg-drafts/issues/5731 The final spec says that only a minimal set of properties is allowed, and those cannot load resources or otherwise expose timing attacks that inform of a user's dictionary. The reported styles (to JS, to DevTools) do not depend on whether or not the style is currently applied, so do not reveal anything about the state of the styled text.

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

None

Debuggability

Devtools support is the same as ::selection, ::target-text, and ::highlight(), which appear in the Styles panel. Properties inherited from ancestor spelling and grammar styles are also shown in the Styles panel.

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

Yes

There are no platform specific aspects to the feature and it is useful on all platforms.

Is this feature fully tested by web-platform-tests?

Yes

https://wpt.fyi/results/css/css-pseudo?label=experimental&label=master&aligned Internal web tests have greater coverage because there is no way in WPT to activate a spelling or grammar error. https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/web_tests/paint/markers/ https://source.chromium.org/search?q=spelling-error&ss=chromium%2Fchromium%2Fsrc https://source.chromium.org/search?q=grammar-error&ss=chromium%2Fchromium%2Fsrc

Flag name on chrome://flags

experimental-web-platform-features

Finch feature name

CSSSpellingGrammarErrors

Non-finch justification

The feature is new and poses no performance or crash risk. It has been in experimental for a long time already and is extensively tested.

Requires code in //chrome?

False

Tracking bug

https://crbug.com/1163437

Sample links

https://bucket.daz.cat/work/igalia/0/1.html

Estimated milestones

DevTrial on desktop

89

DevTrial on Android

89

Anticipated spec changes

The spec has stabilized and there is only one outstanding issue seeking clarification that is not expected to result in a change in behavior.

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/4811776539492352

Links to previous Intent discussions

Intent to prototype: https://groups.google.com/a/chromium.org/g/blink-dev/c/8UEcRJViPEU

This intent message was generated by Chrome Platform Status.

Yoav Weiss

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Nov 1, 2023, 4:26:17 AM11/1/23

to Stephen Chenney, blink-dev

On Tue, Oct 31, 2023 at 1:37 AM Stephen Chenney <sche...@chromium.org> wrote:

The CSS Spelling and Grammar feature has been active behind experimental web platform features since M89! There are no open bugs. I would like to turn it on at last for M120.

Contact emails
sche...@chromium.org, daza...@igalia.com

Explainer
https://drafts.csswg.org/css-pseudo-4/#selectordef-spelling-error
https://drafts.csswg.org/css-pseudo-4/#selectordef-grammar-error
https://drafts.csswg.org/css-text-decor-4/#valdef-text-decoration-line-spelling-error
https://drafts.csswg.org/css-text-decor-4/#valdef-text-decoration-line-grammar-error

Specification
https://drafts.csswg.org/css-pseudo-4/#selectordef-spelling-error

Summary
CSS highlight pseudo-elements for styling text that the UA has flagged as misspelled or grammatically incorrect, and line decorations exposing the UA’s default decorations for spelling and grammar errors. These features allow authors to choose more legible colors for the default spelling and grammar errors, highlight misspelled words with background colors or other decorations, and implement custom spell checking with almost-native appearance.

Blink component
Blink>CSS

Search tags
spelling-error, grammar-error, highlight pseudos

TAG review
None

Can you file a TAG review?

TAG review status
Not applicable

Risks

Interoperability and Compatibility
https://developer.mozilla.org/en-US/docs/Web/CSS/::spelling-error https://developer.mozilla.org/en-US/docs/Web/CSS/::grammar-error

Gecko: No signal (https://github.com/mozilla/standards-positions/issues/470)

WebKit: In development (https://lists.webkit.org/pipermail/webkit-dev/2021-January/031660.html) WebKit has an old WIP patch from 2018 at https://webkit.org/b/175784 CSS Working group minutes imply Safari is planning an implementation: https://github.com/w3c/csswg-drafts/issues/7522

Can you file an official position?

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Rune Lillesveen

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Nov 1, 2023, 5:19:15 AM11/1/23

to Stephen Chenney, blink-dev

On Tue, Oct 31, 2023 at 1:37 AM Stephen Chenney <sche...@chromium.org> wrote:

The CSS Spelling and Grammar feature has been active behind experimental web platform features since M89! There are no open bugs. I would like to turn it on at last for M120.

Finch feature name
CSSSpellingGrammarErrors

Please remove base_feature: "None" from runtime_enabled_features.json5

--

Rune Lillesveen

Stephen Chenney

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Nov 3, 2023, 12:22:20 PM11/3/23

to Yoav Weiss, blink-dev

On Wed, Nov 1, 2023 at 4:26 AM Yoav Weiss <yoav...@chromium.org> wrote:

On Tue, Oct 31, 2023 at 1:37 AM Stephen Chenney <sche...@chromium.org> wrote:
The CSS Spelling and Grammar feature has been active behind experimental web platform features since M89! There are no open bugs. I would like to turn it on at last for M120.

Contact emails
sche...@chromium.org, daza...@igalia.com

Explainer
https://drafts.csswg.org/css-pseudo-4/#selectordef-spelling-error
https://drafts.csswg.org/css-pseudo-4/#selectordef-grammar-error
https://drafts.csswg.org/css-text-decor-4/#valdef-text-decoration-line-spelling-error
https://drafts.csswg.org/css-text-decor-4/#valdef-text-decoration-line-grammar-error

Specification
https://drafts.csswg.org/css-pseudo-4/#selectordef-spelling-error

Summary
CSS highlight pseudo-elements for styling text that the UA has flagged as misspelled or grammatically incorrect, and line decorations exposing the UA’s default decorations for spelling and grammar errors. These features allow authors to choose more legible colors for the default spelling and grammar errors, highlight misspelled words with background colors or other decorations, and implement custom spell checking with almost-native appearance.

Blink component
Blink>CSS

Search tags
spelling-error, grammar-error, highlight pseudos

TAG review
None

Can you file a TAG review?

https://github.com/w3ctag/design-reviews/issues/913

TAG review status
Not applicable

Risks

Interoperability and Compatibility
https://developer.mozilla.org/en-US/docs/Web/CSS/::spelling-error https://developer.mozilla.org/en-US/docs/Web/CSS/::grammar-error

Gecko: No signal (https://github.com/mozilla/standards-positions/issues/470)

WebKit: In development (https://lists.webkit.org/pipermail/webkit-dev/2021-January/031660.html) WebKit has an old WIP patch from 2018 at https://webkit.org/b/175784 CSS Working group minutes imply Safari is planning an implementation: https://github.com/w3c/csswg-drafts/issues/7522

Can you file an official position?

Yes. https://github.com/WebKit/standards-positions/issues/95 Supports.

Mike Taylor

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Nov 6, 2023, 10:23:01 AM11/6/23

to Stephen Chenney, blink-dev

Hi Stephen,

Could you please request reviews for all the other review gates in your chromestatus entry?

thanks,
Mike

Stephen Chenney

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Nov 6, 2023, 7:28:09 PM11/6/23

to Mike Taylor, blink-dev

Thanks Mike.

On Mon, Nov 6, 2023 at 10:22 AM Mike Taylor <mike...@chromium.org> wrote:

Hi Stephen,

Could you please request reviews for all the other review gates in your chromestatus entry?

Yes, done. Sorry I overlooked that.

Mike Taylor

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Nov 6, 2023, 7:58:57 PM11/6/23

to Stephen Chenney, blink-dev

Thanks - LGTM1

Daniel Bratell

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Nov 8, 2023, 10:24:41 AM11/8/23

to Mike Taylor, Stephen Chenney, blink-dev

LGTM2

This one could use a ping in the mozilla standards position issue like that other one.

/Daniel

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/fc13402f-f90d-4b0f-923b-695470717369%40chromium.org.

Yoav Weiss

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Nov 8, 2023, 10:32:49 AM11/8/23

to Daniel Bratell, Mike Taylor, Stephen Chenney, blink-dev

LGTM3

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/44bcfbd7-35cf-4ce4-970d-1754f4cd2e05%40gmail.com.

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