Posted by Alan J. Flavell on 09/05/05 23:11

On Mon, 5 Sep 2005, Larry Lindstrom wrote:

> What do people think of the W3Schools tutorials?

Mixed. Some is fine, some is dubious. I don't know how a would-be
learner could tell the difference.

Usenet is the same, but at least some of the contributors will point
you at authoritiative sources where you can verify the truth for yourself.

> I don't mind caches. But I'm wondering if it
> seems like a flaw in the browser that a non technical
> user, with no knowledge of caches, can't hit the
> "Reload current page" icon and get the current page
> from the server.

It's a fact of the HTTP architecture that if a server says a document
is good for 30 days, it's good for 30 days, even if, after 7 days,
something comes up that means it has to be updated.

Authors need to learn that once that's happened, there isn't a damned
thing they can do from the server side to negate it. Typically, they
react by stubbornly introducing a whole menagerie of immediate-expiry and
no-cache headers that don't solve the actual problem at all, but store up
any amount of trouble for the future.

Users need to learn that, if in doubt, their browser has a gesture (could
be shift/reload or ctrl/reload or whatever) that will break-through any
specification-conforming cache, and get the server's current offering,
even if its previous offering hasn't yet expired.

Nobbling the browser to always do that without the user specifically
requesting it could result in an unnecessarily lethargic response from
servers in general. It's a difficult compromise.

h t h

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