Proposal: extend FocusOptions to allow specifying `:focus-visible` behavior.

[emilio]

Right now, whether to show focus rings on programmatic focus is left up to the User Agent (see #6523 for some background etc).

The heuristics browsers use are mostly interoperable, but they do not cover all use cases. In Mozilla bug 1765083, someone details a use-case for forcing focus rings on programmatic focus (even when focus comes from the mouse). I think that use case is compelling, quoting:

Javascript is often used to validate a form and to set focus on an element that does not meet validation. Especially on complex forms, it can be hard for the end-user to draw their attention to the element without the aid of a focus ring.

It makes sense to show the focus ring even if the form submission was done via the mouse. Similarly, Firefox already has internal use cases for not showing the focus rings even when there hasn't been any previous focus move (which would show rings otherwise), see bug 1699259.

I think it would make sense to extend FocusOptions with something like this:

  boolean focusVisible;

To let authors override the focus ring heuristics that the UA implements.

How does something like that sound? I think it would be reasonably straight-forward to implement interoperably and would give more flexibility to web developers.

I think at least the option to force focus rings should be uncontroversial, as the result should never be less accessible than the alternative. The option to force remove focus rings might be a bit more debatable, but I think it probably makes sense.

cc @mrego @mfreed7 @rniwa

[mrego]

I guess trying to be smart about when to show it or not won't catch all the use cases, as we're seeing. So maybe this could be a solution for that problem.

I wonder what people that were involved in the :focus-visible definition and initial discussions think about this. So adding a few more people on CC @alice @robdodson @bkardell

[domenic]

Any reason for the name focusRing instead of focusVisible?

Also, we don't need to make it nullable; it's a dictionary member so it would already be optional.

[emilio]

Any reason for the name focusRing instead of focusVisible?

Not really, I just made the name up. focusVisible sounds good to me :-)

Also, we don't need to make it nullable; it's a dictionary member so it would already be optional.

Ah, indeed. Updated the OP to account for that.

[craigkovatch]

I enthusiastically support this proposal! I just switched Tableau's internal UI library over to use :focus-visible and am now playing whack-a-mole with a bunch of edge cases that this would solve. For example WICG/focus-visible#268

IMO we should also expose the current "focus-visibility" as a property in FocusEvent, alongside.