if-modified-since question (protocol problem?)

Giganews Newsgroups
Subject: if-modified-since question (protocol problem?)
Posted by:  hug (contact_in…@sig_line.clickit)
Date: Sun, 07 May 2006

[originally posted in alt.www.webmaster, was suggested that this ng
could be a better place.]

I've updated my test server to handle if-modified-since.  I've noticed
that the (old copies I run of) IE and Netscape seem never to send
if-modified-since.  But the strange thing is that Opera sends
if-modified-since but when I reply with "HTTP/1.0 304 Not Modified" it
is not refreshing the screen from its cache, it is leaving the screen

I can only conclude that either I am not returning a correct protocol
sequence including "HTTP/1.0 304 Not Modified", or that the old Opera
I'm running contains a bug.  I'm betting on the incorrect response in
my code.

Anybody have experience with handling if-modified-since themselves and
doing it properly?