[Shadow]: inappropriate reference to CSS3-UI nav-index spec in focus navigation order (bugzilla: 28079)

[hayatoito]

Title: [Shadow]: inappropriate reference to CSS3-UI nav-index spec in focus navigation order (bugzilla: 28079)

Migrated from: https://www.w3.org/Bugs/Public/show_bug.cgi?id=28079

---

comment: 0
comment_url: https://www.w3.org/Bugs/Public/show_bug.cgi?id=28079#c0
Takayoshi Kochi wrote on 2015-02-23 05:24:54 +0000.

The current shadow DOM spec specifies the focus navigation order of
elements in the shadow tree using CSS3 UI's "nav-index" property[1](more specifically in its algorithm 1.3.2 and 2.3, the spec refers to
"auto" for nav-index CSS property).

It's better to rewrite this part to refer to HTML spec, rather than
CSS3 UI spec.

The property is considered "at risk" in the CSS3 UI spec, and might not
be adopted as is in the current spec draft. I found some discussion in
CSS WG's meeting notes[2].

As far as I read the CSS3 UI spec, the "auto" value corresponds to the
behavior of HTML attribute "tabindex" with its value 0 (cf, the spec
is [3] or [4]), which is already implemented in most browsers and the
spec is stable.

[1] http://www.w3.org/TR/css3-ui/#nav-index
[2] https://lists.w3.org/Archives/Public/www-style/2015Jan/0406.html
[3] https://html.spec.whatwg.org/multipage/interaction.html#the-tabindex-attribute
[4] http://www.w3.org/TR/html5/editing.html#sequential-focus-navigation-and-the-tabindex-attribute

[hayatoito]

Now the spec refers CSS3-UI only for directional focus navigation, which is not defined in HTML Standard.