<marquee> only fires start event when it's displayed

[ayg]

When a marquee element is created, the user agent must queue a task to fire an event named start at the element.
https://html.spec.whatwg.org/#the-marquee-element

This doesn't match browser behavior (I intend to post tests today). Neither Edge nor Firefox fire the event until the element is added to a document. Edge also doesn't fire it for a marquee that's display: none, although Firefox does. I would say the spec should follow Edge, all else being equal, because they made up the feature.

(Chrome and WebKit do not implement marquee events AFAICT.)

[domenic]

If they do not implement marquee events, maybe we should just remove them instead?

[Yay295]

Since it's marked as obsolete, should we really be changing anything about its specification?

[annevk]

@Yay295 browsers are still required to support it (due to content using it) so therefore the specification needs to be accurate.

[ayg]

I have no objection to getting rid of these, assuming Gecko is willing to drop support. I filed a bug to add use counters: https://bugzilla.mozilla.org/show_bug.cgi?id=1392710

There's a Chromium bug to support marquee events that's closed as wontfix: https://bugs.chromium.org/p/chromium/issues/detail?id=522326

[ayg]

I submitted a patch on the Mozilla bug to add use counters, although I won't be able to follow up on it unless I find someone to continue to employ me to work on web standards.