Implement form keyboard navigation

[Manishearth]

(Not sure if there is a spec for this)

It's not as simple as it seems. For example, when tabbing out of a radio button, you need to tab to the next radio button only if no button in that group is selected, else you skip the radio buttons in the same group.

[jdm]

https://html.spec.whatwg.org/multipage/#sequential-focus-navigation seems relevant but doesn't discuss input elements, and https://html.spec.whatwg.org/multipage/forms.html#radio-button-state-(type=radio) doesn't mention anything about focus or inertness.

[brunoabinader]

I believe @kmcallister has an experimental patch that provides such functionality, am I right?

[jdm]

Not that I'm aware.

[kmcallister]

Nope, I was just hooking key events directly for my own purposes, nothing to do with forms.

[jdm]

I don't actually think that keyboard-based focus navigation is a blocker for effective dogfooding. Nice to have, for sure.

[jmcomets]

Hi everyone!
I'm reviving this thread after looking through #12071. The patch seemed more like a quickfix to me, it seems awkward that TriggerDefaultAction is returned when handling a tab key event for an input element.

IMHO the tab key handing should be implemented globally, as it cycles the "currently focused area". It doesn't seem like anything's in place to do this though.

I'll open a PR that cleans up #12071 in a bit and look into implementing tab navigation.
Any thoughts?

[jdm]

Note, @nerith has been working on this and there's an in-progress PR at #13460. Thanks for your interest, however! Perhaps there is something you can contribute to that work.

[jmcomets]

From the look of the commits, it looks exactly like what I was hoping for. The PR looks quite finished now, I'll probably contribute elsewhere. Thanks for the update!

[jdm]

#15936 is the most recent effort. It's a good start, but there is a bunch more work that needs to go into it before it's ready to merge. The original author is no longer able to work on it.

[spastorino]

@jdm after returning from my long vacation will start working on it.

[jdm]

Note: said vacation ends in May, so this is available for other people to work on before that time.

[CYBAI]

@jdm I'd like to try to take the #15936 one from @nox and try to finish it. Thanks!