Remaining accessibility issues

[alice]

Basic:

• Focus state (#12)
• Move focus and aria properties outside of shadows
  • As discussed, this will mean that aria relationship attributes can be used with this element before such a time as we can use query selectors
  • It's also the way <input type="range"> works: despite appearances, the slider knob never actually gets focus, it's just drawn that way
• Suggestion: if no scale is present, omit aria-valuetext and allow the AT to speak the value however it wants (e.g. "volume 34%" is more meaningful than "volume 34")
• Encourage authors to use aria-labelledby to associate labels with controls
• Or, alternatively, inherit from <input type="range"> and you will be able to use <label> elements.

Advanced:

• Support all keyboard interactions noted in http://www.w3.org/TR/wai-aria-practices/#slider (including pgUp/pgDown/home/end)

[dfreedm]

Pretty annoying that <label> only works for a few elements.

[alice]

Perhaps we should file a bug on https://html.spec.whatwg.org/multipage/forms.html#category-label

However, it might need more work, since presumably there is some common attribute of labellable elements, which it might be good to expose as some kind of flag for custom elements.

[mgiuffrida]

If the "pin" attribute is set, or if "step" is set, then clicking on the slider or dragging the circle with the mouse doesn't set keyboard focus on the slider -- the arrow keys don't do anything unless you tab to the slider.