> Is there a proposal for anything like an INCLUDE tag?
> e.g. <include src="http://www.xyz.com/standard-footer.html">
> This would have the same structure as IMG but would allow something
> from the server to be included BEFORE the page is processed.
The original HTML 1 documentation suggested that <A>
might be used for this: <A REL="EMBED" HREF="http://www.xyz.com/...">.
(I think the intent was that inlined images could be specified
this way too, before <IMG> was invented for Mosaic.)
The current status of REL and REV semantics are up in the air;
I doubt that REL=EMBED will end up being specified
to work this way.
Netscape has invented an <EMBED> element, and deployed in
the Windows version, but they haven't proposed it
(or even *mentioned* it) on any of the discussion lists
as far as I know. Not sure if it's exactly what you want.
SGML has a mechanism for doing this, namely entity references:
<!doctype html system [
<!entity footer SYSTEM "http://www.xyz.com/std-footer.html">
but only emacs-w3 supports it and most other browsers barf
on the entity declaration and internal DTD subset.
Panorama should be able to handle this too.
Some servers will do "server-side includes", but as
you point out they defeat caching.
"Client-side includes" are probably undeployable by now.
Even if a mechanism were specified, nobody would use it
because current browsers wouldn't process it correctly,
and if nobody uses it, browser authors won't bother