Make 'autofocus' a global attribute

[tkent-google]

• Add 'autofocus' to the global attribute list
• Move 'autofocus' IDL attribute from HTMLButtonElement, HTMLInputElement,
  HTMLSelectElement, HTMLTextAreaElement to HTMLOrSVGElement

This fixes #4563

• At least two implementers are interested (and none opposed):
  • Chrome: I support.
  • Safari
  • Firefox
• Tests are written and can be reviewed and commented upon at:
  • html: Add a test for 'autofocus' as a global attribute web-platform-tests/wpt#18558
• Implementation bugs are filed:
  • Chrome: https://bugs.chromium.org/p/chromium/issues/detail?id=995679
  • Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1575154
  • Safari: https://bugs.webkit.org/show_bug.cgi?id=200913

(See WHATWG Working Mode: Changes for more details.)

---

/dom.html ( diff )
/form-control-infrastructure.html ( diff )
/form-elements.html ( diff )
/index.html ( diff )
/indices.html ( diff )
/input.html ( diff )
/interaction.html ( diff )
/interactive-elements.html ( diff )
/origin.html ( diff )

[domenic]

LGTM. I guess it is pretty simple. I will push an additional sentence or two to tweak the main autofocus section to make it clearer in the non-normative introductory prose that it works on all elements. (The processing model already seems to work on all elements, although the processing model is also being fixed in #4763.)

[tkent-google]

The current PR moves the IDL attribute to HTMLOrSVGElement because it has focus(). However, it implies any SVG element can have 'autofocus' content attribute, right? Should I propose adding autofocus to SVG common attributes, or should I move the IDL attribute to HTMLElement instead of HTMLOrSVGElement?

[domenic]

Interesting question. In the past SVG folks have been excited about unifying where possible. In my opinion it is safe to tentatively assume they will want to do the same here, but we should open an issue and/or pull request to check. /cc @AmeliaBR

[AmeliaBR]

I haven't heard any demand for autofocus in SVG, but if it's being extended in HTML to all elements that can be focusable, it would definitely be preferable (IMO) to keep SVG consistent.

Adding the IDL property to HTMLOrSVGElement handles the DOM side of things, but we do need to define the attribute separately to keep it coordinated.

@tkent-google Are you able to make a PR on the SVG spec (to the Common/core attributes section you linked to, probably add it after tabindex & link back to HTML for all technical details)? Or if you're not sure where to make the edits, at least file an issue so we can track.

[tkent-google]

ok, I filed an issue for SVG; w3c/svgwg#726

[tkent-google]

Made a WPT PR; web-platform-tests/wpt#18558

[smaug----]

Looks reasonable (and should be quite easy to tweak Gecko to have this behavior).

[sideshowbarker]

heads-up @whatwg/documentation