LGTM1
On Wednesday, December 10, 2025 at 8:02:23 PM UTC+1 Bramus Van
Damme wrote:
On Wednesday, December 10, 2025 at 5:09:57 PM UTC+1 Rick
Byers wrote:
Hey David,
This seems fairly straightforward to me, but I imagine
there's probably some developer signals here, right?
Somebody who has said why they want this?
Hi, it’s me! :)
This is needed when applying scroll-triggered animations
that use selectors which match multiple elements. Without
trigger-scope, the last element that declares the trigger
would “win”, thereby breaking all other matched element that
use the same name for its trigger. With trigger-scope, the
name can be contained to a specific subtree, allowing name
reuse.
See
https://codepen.io/bramus/pen/dPMVoYR/2e5fd8b6a35cc77cfb8faf0f16caf1e3
<https://codepen.io/bramus/pen/dPMVoYR/2e5fd8b6a35cc77cfb8faf0f16caf1e3>
(Canary with flags) for an example: each image animates
individually, each with their own trigger-timeline named --t.
Without timeline-trigger scope, all images would animate
using the timeline-trigger of the very last element – which
is not what you want.
tl;dr Without trigger-scope, it would be near impossible for
authors to properly implement scroll-triggered animations.
I'm hearing similar arguments from devs inside of Shopify.
Thanks,
Rick
On Tue, Dec 9, 2025 at 4:40 PM David Awogbemila
<[email protected]> wrote:
*Contact emails*
[email protected]
*Explainer*
https://github.com/explainers-by-googlers/scroll-triggered-animations/blob/main/TRIGGER_SCOPE.md
<https://github.com/explainers-by-googlers/scroll-triggered-animations/blob/main/TRIGGER_SCOPE.md>
*Specification*
https://drafts.csswg.org/css-animations-2/#trigger-scope
<https://drafts.csswg.org/css-animations-2/#trigger-scope>
*Summary*
trigger-scope gives authors the ability to limit the
names of animation triggers declared by
trigger-instantiating properties.
Trigger-Instantiating properties, such as
timeline-trigger, declare names which can be
referenced by the animation-trigger property in
order to attach animations to triggers. However,
these names are global by default (similar to
anchor-name) and it is often useful for author to
limit the visibility of the names so as to isolate
animation-to-trigger interactions.
*Blink component*
Blink>Animation
<https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EAnimation%22>
*Web Feature ID*
Missing feature
*Motivation*
Similar to anchor-scope[1], trigger-instantiating
properties need a mechanism for limiting the
visibility of the names declared by the
trigger-instantiating property. [1]
https://drafts.csswg.org/css-anchor-position-1/#anchor-scope
<https://drafts.csswg.org/css-anchor-position-1/#anchor-scope>
*Initial public proposal*
/No information provided/
*TAG review*
https://github.com/w3ctag/design-reviews/issues/1175
<https://github.com/w3ctag/design-reviews/issues/1175>
*TAG review status*
Pending
*Risks*
*Interoperability and Compatibility*
/No information provided/
/Gecko/: No
signal
(https://github.com/mozilla/standards-positions/issues/1327
<https://github.com/mozilla/standards-positions/issues/1327>)
/WebKit/: No
signal (https://github.com/WebKit/standards-positions/issues/589
<https://github.com/WebKit/standards-positions/issues/589>)
/Web developers/: No signals
/Other signals/:
*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*
/No information provided/
*Will this feature be supported on all six Blink
platforms (Windows, Mac, Linux, ChromeOS, Android,
and Android WebView)?*
Yes
*Is this feature fully tested by web-platform-tests
<https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?*
Yes
https://wpt.fyi/results/?label=master&label=experimental&aligned&q=trigger-scope
<https://wpt.fyi/results/?label=master&label=experimental&aligned&q=trigger-scope>
(As
of this writing, only the parsing tests are present
on the dashboard but functional tests[1] are quickly
following) [1]
https://github.com/web-platform-tests/wpt/pull/56601
<https://github.com/web-platform-tests/wpt/pull/56601>
*Flag name on about://flags*
/No information provided/
*Finch feature name*
/No information provided/
*Non-finch justification*
/No information provided/
*Rollout plan*
Will ship enabled for all users
*Requires code in //chrome?*
False
*Tracking bug*
https://crbug.com/466134208
*Estimated milestones*
Shipping on desktop145Shipping on Android145Shipping
on WebView145
*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/5152759609425920?gate=5794840308744192
<https://chromestatus.com/feature/5152759609425920?gate=5794840308744192>
This intent message was generated by Chrome Platform
Status <https://chromestatus.com/>.
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