Move dataset & other shared IDL attributes from SVGElement to HTMLOrSVGElement

[jarek-foksa]

The current draft of the SVG spec defines dataset attribute on the SVGElement interface while HTML 5 spec defines it on the HTMLElement interface.

Is there any particular reason why dataset couldn't be defined just once on the Element interface like other similar attributes such as classList?

[AmeliaBR]

I don't think dataset can be generalized to all XML languages (because of the expectations it creates re valid attributes), so putting it on Element is unlikely to happen.

However, it may be preferable to define it within the DOM specs as a "mixin" interface that can then be implemented by both HTMLElement and SVGElement. That would ensure that we had one, canonical definition that would always be updated consistently.

Anyone want to take responsibility for looking into this possibility with HTML WG and WHATWG?

[dstorey]

There is now a PR for this and blur/focus/tabindex in HTML whatwg/html#3543