[whatwg] seamless iframes and event propagation

Anne van Kesteren annevk at annevk.nl
Wed Dec 5 09:48:25 PST 2012

On Wed, Dec 5, 2012 at 4:38 PM, Dimitri Glazkov <dglazkov at chromium.org> wrote:
> Yes, the intent is that in the the events from nodes, distributed to
> insertion points should feel as if there wasn't any shadow tree around them.

Right, but if <img> is inside the shadow tree (rather than distributed
into it), you do not want its load/error events to leak? (Again, it
would help if the principles behind those events were written down,
e.g. soonish <img> will start dispatching progress events and who
knows what it might dispatch in the future. That list does not address
<video> either if the same would apply to that element.)

So what I want is to tie this into the DOM's dispatch algorithm. The
dispatch algorithm somehow needs to compute the ancestor chain and the
current plan to do that is to follow an "event parent" chain (each
EventTarget would have an "event parent" which is either null or some
other object). However, it seems that is not quite enough for shadow
DOM so instead we need to determine the "event parent" of an object
algorithmically. I think we want "event parent for /event type/". So
e.g. on ShadowRoot objects the "event parent for load" would be null,
whereas for unicorn it would be its host element.

Does that make sense?

Ian, for HTML that would allow easily dealing with the load exception
on Window too.


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