- From: David A via GitHub <noreply@w3.org>
- Date: Mon, 06 Oct 2025 18:08:17 +0000
- To: public-css-archive@w3.org
Talked with @ydaniv and @flackr offline and we have agreed to use the keywords in the [table above](https://github.com/w3c/csswg-drafts/issues/12611#issuecomment-3292998336). The **proposal** we want to resolve on is this: `animation-trigger` specifies the behavior of triggers using the keywords in the [table above](https://github.com/w3c/csswg-drafts/issues/12611#issuecomment-3292998336). For completeness, here is the proposed syntax in full: `animation-trigger: [ [ <dashed-ident> <enter-behavior> [<exit-behavior>] ]+ ]#` where: - `<enter-behavior>` and `<exit behavior>` are each declared using one of the keywords in the table. - `<exit-behavior>` is optional and is `none` when omitted. --- Additionally, we considered supporting `auto` as a keyword for the `<exit-behavior>`. `auto` would mean "same as \<enter-behavior\>". As such, we propose the following: - add `auto` to the list of \<exit-behavior\> keywords, meaning "same as \<enter-behavior\>", and - let \<exit-behavior\> default to `auto` The benefit of setting `auto` as the default `<exit-behavior>` is that in some cases it simplifies what authors need to specify. I'll describe how `auto` affects the higher-level [behaviors](https://drafts.csswg.org/web-animations-2/#trigger-behaviors) we hope to keep support for: - **Once** is achieved with `animation-trigger: --trigger play-once` - this behavior remains unchanged, - **Repeat** is achieved with `animation-trigger: --trigger play reset` which, since it specifies the exit keyword, keeps the behavior unchanged, - **Alternate** is achieved with `animation-trigger: --trigger play-forwards play-backwards` but, with the `auto` modification, can be simplified to `animation-trigger: play-alternate`, - **State** is achieved with `animation-trigger: --trigger play pause` which, since it specifies the exit keyword, keeps the behavior unchanged, The caveat is that in some cases, having the \<exit-behavior\> mirror the \<enter behavior\> may not be desirable, e.g. `animation-trigger: --timeline-trigger play` is perhaps not intended to `play()` on exit. However, we think this is mitigated because: 1. most use cases likely fall into the categories described above, and 2. this case is easily fixed with `animation-trigger: --timeline-trigger play none` cc @ydaniv @flackr on any correction in the `auto` proposal. -- GitHub Notification of comment by DavMila Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/12611#issuecomment-3373164609 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Monday, 6 October 2025 18:08:18 UTC