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

From: Amelia Bellamy-Royds via GitHub <sysbot+gh@w3.org>
Date: Mon, 04 Jun 2018 23:08:02 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-394528387-1528153681-sysbot+gh@w3.org>
The current [spec text in css-animations](https://drafts.csswg.org/css-animations-1/#keyframes) is very explicit, but probably isn't consistent with the current intention:

> 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. None of the properties interact with the cascade (so using `!important` on them is invalid and will cause the property to be ignored).

The transition properties aren't defined in css-animations, so they wouldn't be covered by that rule.

It should probably be rewritten to focus on whether or not the property is animatable, as defined in [CSS Transitions](https://drafts.csswg.org/css-transitions/#animatable-properties) (factoring in the current definition of "animatable" as separate from "interpolate-able").

Regardless, Brian has a good point about CSSOM: for properties that aren't animatable/allowed in keyframes, should they be dropped by the parser, or should they be accepted by the parser but ignored as far as applying the animation?

The same section later says:

> The `<keyframe-block>` contains properties and values. The properties defined by this specification are ignored in these rules, with the exception of animation-timing-function, the behavior of which is described below. In addition, properties qualified with !important are invalid and ignored.

Which seems to imply there is a difference between "ignored" declarations and "invalid and ignored" declarations.

GitHub Notification of comment by AmeliaBR
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/2736#issuecomment-394528387 using your GitHub account
Received on Monday, 4 June 2018 23:08:05 UTC

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