Instead of intelligent guesses, here is an informed answer:

HTML 5 plans to allow peer to peer connections from javascript, but these connections WILL NOT BE RAW TCP.

The complete spec can be found at http://dev.w3.org/html5/websockets/

jrh

EDIT: with specific reference to peer to peer connections, check out these links:

Its important to note that the capabilities are still being negotiated. It will be nice to be able to create "local chat" web apps :)

jrh