RFC 5988 re-introduces the Link: header, last seen in RFC 2068 (and not RFC 2616!).
The Link header has lots of uses; one less-confusing such use is to use it for rel=prefetch, and rel=subresource allowing server side indication of important resources in advance of a document parse.
Implement the link header.
I'm wondering what the difference between link=prefetch and link=subresource is. I couldn't find the latter documented anywhere.
Is this the same as prefetch, but delaying load event?
> I'm wondering what the difference between link=prefetch and link=subresource is. I couldn't find the latter documented anywhere.
I believe prefetch is a low priority load (so it waits until all the other resources for the page are loaded before clogging up the network) whereas subresource is a high priority load that tries to load the resource in time before its needed by the same page.
To be clear about my first comment, I think the initial implementation of the Link header should shy away from rel types that mutate or affect data; so let's stick with rel=prefetch, rel=subresource, rel=dns-prefetch and possibly rel=icon.
Test cases: http://greenbytes.de/tech/tc/httplink/
What is the state of this bug? We have implemented Link header for mobile and I was disappoint why nobody implement it well.