[patch] [cla] on(node, "focusin", ...) calls listener too late on IE9+

[bill]

on.js has code for map "focusin" and "focusout" types to "focus" and "blur" for browsers that don't support "focusin" and "focusout" natively:

if(has("dom-addeventlistener")){
        // normalize focusin and focusout
        captures = {
                focusin: "focus",
                focusout: "blur"
        };
        ...

However, this code runs for IE9+, firefox, and chrome, whereas it ​really should only run for firefox.

In particular this leads to problems on IE where on(node, "focusin", listener) calls the listener asynchronously. I hit it after [30957] and I guess it led to many of the fixes/workaround in #16926, but #16968 is trickier so perhaps we should fix the real bug rather than working around it.

[bill]

(In #16968) It turns out this started with [30957] with the root cause of #16970.

[bill]

I'm attaching a patch, does it look OK? True feature testing is quite difficult since webkit supports focusin but there's no clue like element.onfocusin being defined. The true feature test (as listed in ​http://stackoverflow.com/questions/7337670/how-to-detect-focusin-support) requires attaching an element to the document and actually focusing it, which seems a bit crazy.

For now I just check if element.attachEvent is defined. It's similar to the current code which checks whether element.addEventListener is defined, except that it does the right thing on IE9+ by listening to focusin instead of focus. (To put it another way, you shouldn't assume that addEventListener("focusin", ...) doesn't work just because addEventListener() is defined.)

[bill]

simple patch to stop using workaround code for IE9+, and just use it for firefox (where it's needed) and webkit (where it doesn't hurt)

[Kris Zyp]

This looks like a good patch, go ahead and commit it.

[bill]

In [31152]:

Use IE's native focusin/focusout support for IE9+ too, avoiding asynchronous focus notification, fixes #16968, #16970, and refs #16926, #16972 !strict.

[mahays0 <mahays0@…>]

In b9ab7f580c8a123ff07ebd9a3b0695e24cf5c5ba/dojo:

Error: Processor CommitTicketReference failed

Unsupported version control system "git": Can't find an appropriate component, maybe the corresponding plugin was not enabled? 

[bill]

Note: this change is superseded by #17599.