Re: [csswg-drafts] [css-animations] Clarify whether `<keyframes-name>` supports the empty string (#7762)

> > It seems that Firefox accepts `'""'` as a valid `<string>` value, when it shouldn't as agreed here by Tab and Fantasai.
> 
> Not quite. As shown in my testcase:
> 
>     * That^ description (accepting `'""'` as a valid `<string>` value) seems to match what **Safari** does -- they accept the empty string and even use it as the computed value for animation-name.
> 
>     * Chrome also accepts the empty string, and serialize to the empty string, but treat it as `none` by computed-value time.
> 
>     * Firefox accepts the empty string and internally treats it as `none` at parse time (because we literally encode the special `none` value as the empty-string, see [here](https://searchfox.org/firefox-main/rev/4fd0fa7e5814c0b51f1dd075821988377bc56cc1/servo/components/style/values/mod.rs#691-693) in the definition of `KeyframesName` which is the underlying type here.


I'm biased of course :) but personally I think Firefox's behavior (treating a quoted empty-string as an alias for `none`, effectively) seems most-coherent here.

Chrome Canary's behavior seems internally inconsistent.
And Safari's behavior (treating the empty string as fully-valid and usable as an actual computed value) seems broken and seems to be the-most-going-against Tab & Fantasai's preference here.

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Received on Wednesday, 12 November 2025 22:00:35 UTC