Aryeh Gregor (:ayg) (no longer with Mozilla) Assignee
	Description • 7 years ago

After a lot of discussion at <https://github.com/whatwg/dom/issues/362>, we agreed to remove support for a bunch of event types from the list supported in createEvent().  The new list in the spec matches our own exactly, except that it includes FocusEvent, because Chrome usage counters show high usage: <https://www.chromestatus.com/metrics/feature/timeline/popularity/1171>  Currently about 0.04% of pages do createEvent("FocusEvent") in Chrome, which is high enough they'd prefer not to drop support.  Possibly these pages break somehow in Firefox as well.  Either way, I think it's fine for us to add support for this one event type.

	Aryeh Gregor (:ayg) (no longer with Mozilla) Assignee
	Comment 1 • 7 years ago

Sorry, we actually still support some events that the spec doesn't, just FocusEvent is the only type that the spec says to support that we don't.

	Aryeh Gregor (:ayg) (no longer with Mozilla) Assignee
	Comment 2 • 7 years ago

So when creating the event with createEvent(), it initializes the .type to "focus" instead of "", which causes test failures.  I tried looking through the source code a lot until I gave up.  Do you know how to fix it?

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 3 • 7 years ago

What kind of patch do you have?
Do you need something like http://searchfox.org/mozilla-central/rev/b52285fffc13f36eca6b47de735d4e4403b3859e/dom/events/EventDispatcher.cpp#1017 ?

	Aryeh Gregor (:ayg) (no longer with Mozilla) Assignee
	Comment 5 • 7 years ago

I forgot to add, I deliberately didn't add telemetry for this, because I think the decision to add the event is final.  If we ever want to consider dropping it and are worried about usage, we could always add telemetry then.

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 6 • 7 years ago
mozreview-review

Comment on attachment 8894577 [details]
Bug 1388069 - Support createEvent("FocusEvent");

https://reviewboard.mozilla.org/r/165734/#review170860

Sorry, but this has tons of unrelated stuff. Could you just upload a patch for this particular bug.

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 8 • 7 years ago
mozreview-review

Comment on attachment 8894577 [details]
Bug 1388069 - Support createEvent("FocusEvent");

https://reviewboard.mozilla.org/r/165734/#review171298

	Pulsebot
	Comment 9 • 7 years ago

Pushed by ayg@aryeh.name:
https://hg.mozilla.org/integration/autoland/rev/e6fb60951529
Support createEvent("FocusEvent"); r=smaug

	Carsten Book [:Tomcat]
	Comment 10 • 7 years ago
bugherder

https://hg.mozilla.org/mozilla-central/rev/e6fb60951529

	Chris Mills [:cmills]
	Comment 11 • 7 years ago

On MDN, we have a createEvent() page:

https://developer.mozilla.org/en-US/docs/Web/API/Document/createEvent

However, we don't cover the different types of event in detail; we just say how the method is used, link to the DOM standard for the full list of event types that can be created, and then recommend that developers use event object constructors instead. This being the case, I don't think there is all that much update in the docs.

I have however added a note to the Fx57 rel notes to cover it:

https://developer.mozilla.org/en-US/Firefox/Releases/57#DOM