> done by supplying some attributes that are not visible in the HTML browser,
> but would create additional "name=value" pairs that are passed to the server.
> which would not be displayed in the browser, but be passed to the server
> just like the other fields.
This is what the <MH> element in the HTML+ spec is for. It allows authors
to include RFC 822 headers in the request, which are/aren't shown to the
reader according to whether the HIDDEN attribute is missing/present.