Resource Hints on non <link> elements

[igrigorik]

(Moved from igrigorik/resource-hints#10)

The prefetch keyword may be used with link, a, and area elements. [1]

Consider whether it makes sense to expose this for RH, on which elements, and what the motivating use cases are.

[1] http://www.w3.org/TR/html5/links.html#link-type-prefetch

[igrigorik]

prefetch keyword on a + area elements is shorthand for:

<link rel="preload" href=... as="html" loadpolicy="next inert">

As such, UA can automatically translate existing prefetch keyword to above policy. Given that this is pure syntax sugar, I don't think this is a high value feature. Closing for now, we can revisit in the future if there is high demand.

[chicheng]

Isn't <a rel="next prefetch" href="page-2.html">Next page</a> much easier to write manually or implement in CMS than a separate link element? Or people may forget to delete <link rel="dns-prefetch" href="..."> after they removed related a element (which may be hundreds of lines away)