On Tue, Apr 5, 2016 at 10:26 PM, Matt Woodrow <mwood...@mozilla.com> wrote: > Our suggested solution to this is to add a callback to scrollable elements > that fires before painting (similar to requestAnimationFrame) and exposes > the (approximate) region of the element that the UA is going to treat as > visible for the purpose of painting.
This sounds very much like something CSS needs to define, together with the scroll event. https://drafts.csswg.org/cssom-view/ might be a better place I think. The HTML Standard defines when there is an opportunity for scroll events to be dispatched relative to other rendering matters, but not much more. > It might also be nice to extend the IntersectionObserver spec to allow > specifying the renderport (plus a margin) as the intersection region to > observe, so that content can trigger asynchronous loading of data before it > enters the renderport. That suggestion probably best goes here: https://github.com/WICG/IntersectionObserver. Hope that helps. -- https://annevankesteren.nl/
