It's possible, if browsers feel like supporting it. I know of no
browsers that currently provide such support. Netscape's
multipart/x-mixed-replace comes close enough that going to
multipart/mixed doesn't seem like a huge step, but it's not an obviously
"cool" thing to do so who knows.
Also, if you are writing a browser that implements multipart/x-mixed-replace,
please put a "Accept: multipart/x-mixed-replace" in your headers so that we
can compare for that in our server-push scripts rather than performing a
regexp on the user-agent... thanks.
email@example.com firstname.lastname@example.org http://www.[hyperreal,organic].com/