Re: [csswg-drafts] [css-animations] Serialize all keyframe names as strings (#2435)

  > I think all the browser are interoperable now [...]

This seems true only for `animation-name`. Keyframe names also exist in `@keyframes`'s prelude, and are serialized in `CSSKeyframesRule.cssText` and `CSSKeyframesRule.name`.

Based from my observations in [this CodePen](https://codepen.io/creativewave/full/ByjYYrN):

  - Chrome serializes the `<string>` value as an identifier in `@keyframes`, **even if it is an excluded identifier**, and as is in `CSSKeyframesRule.name`
  - Firefox serializes the `<string>` value as an identifier in `@keyframes`, except if it is an excluded identifier, and as is in `CSSKeyframesRule.name`
  - Chrome and Firefox accept any value for `CSSKeyframesRule.name` and serializes it as specified
  - Firefox replaces `""` with `none` in `animation-name` and `@keyframes`, and serializes it as the empty string in `CSSKeyframesRule.name`

The non-conforming behaviors with `""` and `"none"` are unrelated to this issue.

For what is worth, these are the WPT tests related to this issue:

  1. [`animation-name`](https://github.com/web-platform-tests/wpt/blob/master/css/css-animations/parsing/animation-name-valid.html)
  2. [`@keyframes`](https://github.com/web-platform-tests/wpt/blob/master/css/css-animations/parsing/keyframes-name-valid.html)
  3. [`CSSKeyframesRule.name`](https://github.com/web-platform-tests/wpt/blob/master/css/cssom/CSSKeyframesRule.html)

(1) seems complete.

(2) does not test CSS-wide keywords, `default`, and `none`.

(3) does not test any relevant value.

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Received on Monday, 26 January 2026 14:00:05 UTC