Re: [csswg-drafts] [web-animations-1] CSS parsing context for the procedure to process a keyframes argument ?

We discussed this at our telcon in 2018-03-06:

> Suggestion (smcgruer): use the CSS context from the target if non-null, otherwise use the CSS context from the same document as the execution environment for the JS?
>
> birtles: Firefox does the latter: Uses the current realm document from when the KeyframeEffect was created. (See [Bug 1277456](https://bugzilla.mozilla.org/show_bug.cgi?id=1277456))
>
> flackr: Can we always use the current realm from when it was created?
>
> But need to decide what to do about the case where a given (property, value) pair are valid in the execution context where we parse the keyframes, but not in the context where the keyframes are used.
>
> Note that the context for _computing_ the property value is based on the target element:
> "For each property specified in keyframe, calculate the computed value specified on keyframe using the target element as the context for computing values"[1]
> [1] https://drafts.csswg.org/web-animations-1/#calculating-computed-keyframes
>
> This is strictly about the context used for parsing.
> 
> We want to avoid having to store the original string values--implementations should be able to store these values using a more compact form.
>
> Thoughts: Security implications? Same origin frames only though, right?
>
> Imagine switching a target from a secure context to a non-secure context (is this possible?); should we re-parse and drop CSS properties that are no longer valid (e.g. PaintWorklet).
>
> Also quirks mode; if you enable/disable this it can change CSS property parsing we believe?

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Received on Thursday, 12 April 2018 13:34:40 UTC