From what I know, at least Netscape ignores the expires
header. HOWEVER, most HTTP caching program/appliances
will honor the value
That doesn't mean that the page will be reloaded if you
have a proxy cache in between your browser and the server,
for it's the browser that actually determines if it should
verify with the server ( or the proxy cache ) if the
content has expired
The fail safe way is this: You need to use the META
tag in the HTML, as in:
<head>
<meta http-equiv="Expires" content=".......">
....
</head>
This will let major browsers know that the content
will expire at some known time in the future, thus
forcing the browser to reload
At the same time, you should set the HTTP Expires header,
so that if there is a proxy-cache in between the browser
and the server, the contents are more likely to be renewed.
Hope that helps
P.S., of course, you still may want to telnet to your
web server and make sure that it's spitting out the
correct headers that you think it's spitting out... |