Webkit and Moz transition events un-neccessary

[pat@…]

In recent versions of Chrome and Firefox, the vendor prefixes for transitions, animations, and transforms have been removed. This is fine for CSS, but in javascript the vendor-prefixed events fire in addition to the non-prefixed events. This results in transitionend events firing twice in Chrome/Firefox. I'm not sure where this would have an impact in the WP back-end, but I was looking in media-views.js and noticed where the prefixed events are used and thought to myself that it would likely cause an issue somewhere.

[helen]

What versions of those browsers, and what might we need to continue to support for, say, Kindle Fire/Silk?

[jorbin]

the webkit versions need to stay for safari.

the moz versions could possibly go. Support for the prefix free version was added in ff16 (24 is current).

​http://caniuse.com/#feat=css-transitions
​https://developer.mozilla.org/en-US/docs/Web/CSS/transform

[ocean90]

Autoprefixer!

[helen]

If nothing uses -moz- anymore, seems like we could probably drop that. Not -webkit-, though.

[pat@…]

Hm, seems we might need to find a solution then to the multiple events firing in Chrome. If the webkit prefix needs to stay, there should be a detect of some sort to ensure that listeners aren't responding to cloned/prefixed events.

[helen]

I guess as far as the JS (jQuery-specific?) part goes, I'm not convinced that's a WP bug. Seems like that would affect a lot of sites and apps that support a broader level of browser compat.

[pat@…]

I agree, although WP may very well be affected by this behavior, perhaps a patch?

[helen]

Not sure what we should patch in core - is there an actual issue here? I don't think we do (or would do) JS on a transition event.

I'm leaving this open for now because we should probably re-evaluate the -moz- prefix usage.

[helen]

Actually, I'm closing. I don't know what needs to actually be done here - reopen if we find out.