Mike McGuinness wrote:
>
> Another alternative is to be *really* strict:
>
> res.setHeader("Cache-Control", "no-cache");
> res.setHeader("Cache-Control", "no-store");
> res.setHeader("Cache-Control", "private");
> res.setHeader("Cache-Control", "must-revalidate");
> res.setHeader("Expires", "Tue, 25 Dec 1996 12:22:22 GMT");
> res.setHeader("Pragma", "no-cache");
>
> The last one (Pragma) is for http 1.0 and should work on
> most browsers. ... Ref. rfc 2616, section 14.9
>
Yeah, but then section 13.13 has to go and ruin it all
by saying that:
"History mechanisms and caches are different. In
particular history mechanisms SHOULD NOT try to show
a semantically transparent view of the current state
of a resource. Rather, a history mechanism is meant
to show exactly what the user saw at the time when
the resource was retrieved."
In other words: the 'back' button is never supposed to
revalidate, ever. Some people argue that "no-store"
should apply to the history list, but the spec is
pretty clear that it doesn't.
Of course, that's not very practical, and many browsers
correctly ignore the horribly broken section 13.13, but
they all do it in %!&%$ different ways.
Newish versions of Mozilla, for example, will happily
fail to revalidate Pragme: no-cache, but can be convinced
using Cache-Control: no-store.
If you use the "really strict" set of headers listed
above, does IE revalidate? or does it just pop you
back to the previous (stale) page? (When I messed with
this a while back, there were some vesions of IE where
it appeared to be impossible to prevent history-list
caching)
--
Christopher St. John [EMAIL PROTECTED]
DistribuTopia http://www.distributopia.com
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