[whatwg] Proposal: add attributes etags & last-modified to <link> element.

[Aryeh Gregor]

2010/9/19 Julian Reschke <julian.reschke at gmx.de>:
> So it's a workaround that causes a performance optimization. It wouldn't be
> necessary if the linked resource would have the right caching information in
> the first place.

Sure it would.  You can currently only save an HTTP request if a
future Expires header (or equivalent) can be sent.  A lot of the time,
the resource might change at any moment, so you can't send such a
header.  The client has to check every time, and get a 204, even if
the resource changes very rarely.  If you could indicate in the HTML
source that you know the resource hasn't changed, you could save a lot
of round-trips on a page that links to many resources.