Comment 0 for bug 240133

The discussion in Bug 17309 "Wait for primary style sheets before constructing
frames" seems to have gotten bogged down - it seems obvious that no matter
what the final decision is on what to do and how to do it, it can't
be exactly what everyone would want.

Unless the decision is to always block display "forever" while waiting for all
primary style sheets to arrive, which would be sure to vex some, some pages
that cannot be properly displayed will be displayed anyway.

Ensuring that the browser has full rfc2557 MHTML support would provide a viable
mechanism for ensuring that LINKed stylesheets arrive with the documents
they apply to: those who absolutely *need* the stylesheets to arrive before
rendering could send an MHTML document instead on the basis of appropriate
content-negotiation. This would ensure that the HTML, and thinking forward,
XHTML and XML, documents could be made available with certainty that the
necessary stylesheets would be present at page layout time.

This would provide an "escape valve" of sorts to make sure that the issues
in bug 17309 do not become overpressurized. If this feature request is not
adopted, the "correct" fix for 17309 becomes very important due to the lack
of a viable alternative, on the page author's part, to hoping that the
browser does the right thing in even the most adverse conditions (say,
just after another railway crash that takes out a fiber run).

Whether any webserver available now can assemble an MHTML document on the fly
is unknown; whether authors would be willing to use tools to "precompile"
MHTML documents is also unknown.

Quoting from the RFC:
"While initially designed to support e-mail transfer of complete
multi-resource HTML multimedia documents, these conventions can also
be employed to resources retrieved by other transfer protocols such
as HTTP and FTP to retrieve a complete multi-resource HTML multimedia
document in a single transfer or for storage and archiving of
complete HTML-documents." <URL:http://www.faqs.org/rfcs/rfc2557.html>

Regardless of anything else, it is probably a good thing for the browser
to fully support rfc2557 MTHML for maximum flexibility and to open up
future options, particularly regarding XML.

I do see a downside: any simple way of implementing this would be very
cache-inefficient, and any way that would be cache-efficient could conceivably
add enough complexity to require extentions to HTTP.