- From: Ryosuke Niwa via GitHub <sysbot+gh@w3.org>
- Date: Sun, 05 Aug 2018 21:21:37 +0000
- To: public-css-archive@w3.org
> Wouldn't such a request might already be raised for components wanting to know when a composed component changed it's parts? That can be easily done if this were DOM API because then detecting any change to whether a given element is exposed as a part or not is very fast & easy. Detecting whether a arbitrary set of selectors would match or cease to match an element is **extremely expensive** operation. This is why modern browser engines match selectors lazily when updating the styles. > Isn't this already the case with `animationstart` and `transitionstart`? `animationstart` and `transitionstart` are different because they're async events, and the browser already has to know when an animation or a transition starts (in order to start the animation or the transition). Also, CSS animations doesn't start until the next painting / rendering happens, and the browser engine already has to update the style in those cases so detecting whether a given element has an animation or not is virtually cost-free. -- GitHub Notification of comment by rniwa Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/2904#issuecomment-410548945 using your GitHub account
Received on Sunday, 5 August 2018 21:21:40 UTC