> Not Modified 304
>
> If the client has done a conditional GET and access is allowed,
> but the document has not been modified since the date and time
> specified in the If-Modified-Since field, the server responds with
> a 304 status code and does not send the document body to the client.
>
> Response headers are as if the client had sent a HEAD request, but
> limited to only those headers which make sense in this context. This
> means only headers that are relevant to cache managers and which may
> have changed independently of the document's Last-modified date.
> Examples include Date, Server, and Expires.
>
> The purpose of this feature is to allow efficient updates of local
> cache information (including relevant metainformation) without requiring
> the overhead of multiple HTTP requests (e.g. a HEAD followed by a GET)
> and minimizing the transmittal of information already known by the
> requesting client (usually a caching proxy).
-- Cheers, Ari --