Re: [csswg-drafts] [css-animations] Clarify properties that are not allowed in @keyframes rule

For `Keyframe` objects we can just say to skip non-animatable properties but for `@keyframes` rules we need to allow `animation-timing-function`.

In the sentence:

> The `<declaration-list>` inside of `<keyframe-block>` accepts any CSS property except those defined in this specification, but does accept the animation-timing-function property and interprets it specially.

I'm not sure what "accepts" means here (are such properties ignored silently? Do they generate errors? Are they available in the CSSOM?). However, I suspect we want to do what Gecko does here and parse such properties, expose them in the CSSOM, but simply not animate them. i.e. this is Issue 1 from the spec:

> This specification needs to define how the value is determined from the keyframes, like the section on Application of transitions does for CSS Transitions.

That would allow, for example, polyfilling an animation that includes the `display` property (a non-animatable property).

We should also get all those animation types documented in CSS V&U. Perhaps that's something I can follow up on in July.

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Received on Monday, 4 June 2018 22:58:42 UTC