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Originally Posted by SMHarman
Http also has a HEAD command and a GET command. GET asks for the whole page, HEAD asks for the headers, which can be used to compare to the cached headers. Head uses a lot less bandwidth as a result.
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Correct - but there's a way of using even less bandwidth.
If you issue an HTTP GET and also include an If-Modified-Since header then the web server will only send you the object if it has been modified since the date that you specified. If it hasn't, it replies with HTTP/1.1 304 Not Modified and then you can mark your content as being fresh again having only transferred a few bytes.
You can view this in a trace by seeing lots of 304 responses typically coming back after you hit browser Refresh.
But now we're getting away from the 'simple' aspect of this thread ...
