"last updated" attribute on <a>nchors?

[Wes0617]

Would make sense to have a "last updated" attribute on links that affects their style through :visited ?

Also useful for search engines' bots.

Imagine one visits the page "ref.html" that contains:

<style>a:visited{color:purple;}</style>
 <a datetime="2016-07-22 00:00Z" href="page.html">Page</a>

And clicks said link. If they visit "ref.html" again they will see the link in purple. If the page author then updates page.html (+ changes the link in ref.html with the new datetime) and the user visits the page again, they will see the link in blue, because what they visited the last time was an older version of the page.

The datetime attribute could also be refreshed through DOM so that user will get immediate feedback on pages that were updated while standing on the referrer page.

The value of the attribute could (possibly) just reflect the HTTP header Last-Modified, I think.

Opinions?