Intent to Ship: overscroll-behavior: chain

[Chromestatus]

Contact emails

vmp...@google.com

Explainer

https://github.com/vmpstr/htmldemos/blob/master/gestures/overscroll-behavior-chain.md

Specification

https://drafts.csswg.org/css-overscroll-1/#propdef-overscroll-behavior

Summary

overscroll-behavior currently has 3 values: none, auto, and contain. These values affect 2 independent effects: scroll propagation and local border effect (e.g. overscroll stretch). none: no propagation, no local effect auto: propagation, local effect contain: no propagation, local effect This feature tracks a new value to complete the set: chain: propagation, no local effect This is useful for effects like side menus implemented as scrollers. We want to bring the menu in and when it hits the edge it doesn't overscroll (stretch/translate). However, it would then allow scroll chaining to the ancestor. Initial proposal: https://github.com/w3c/csswg-drafts/issues/13370

Blink component

Blink>Scroll

Web Feature ID

overscroll-behavior

Motivation

This feature is useful for effects like side menus implemented as scrollers. We want to bring the menu in and when it hits the edge it doesn't overscroll (stretch/translate). However, it would then allow scroll chaining to the ancestor. There may be other effects that want to prevent overscroll effects but allow chaning

Initial public proposal

https://github.com/w3c/csswg-drafts/issues/13370

TAG review

https://github.com/w3ctag/design-reviews/issues/1228

TAG review status

Pending

Goals for experimentation

None

Risks

Interoperability and Compatibility

No information provided

Gecko: No signal (https://github.com/mozilla/standards-positions/issues/1406)

WebKit: No signal (https://github.com/WebKit/standards-positions/issues/661)

Web developers: No signals We've had some use-cases in other features (overscroll gestures) where this behavior was needed to avoid awkward interactions

Other signals:

Ergonomics

None

Activation

None

Security

None

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?

No information provided

Debuggability

This is debuggable as other CSS properties

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

No

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

Yes
https://wpt.fyi/results/css/css-overscroll-behavior?label=master&label=experimental&aligned&q=overscroll-behavior (Added via https://github.com/web-platform-tests/wpt/pull/59792)

Flag name on about://flags

No information provided

Finch feature name

CSSOverscrollBehaviorChain

Rollout plan

Will ship enabled for all users

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/issues/499018879

Estimated milestones

Shipping on desktop	150
Shipping on Android	150
Shipping on WebView	150

Anticipated spec changes

Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way).

No information provided

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5176802466201600?gate=4784727853760512

Links to previous Intent discussions

Intent to Prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/69ceb225.050a0220.1c79a0.01ba.GAE%40google.com

This intent message was generated by Chrome Platform Status.