See Getting a WebGL Implementation for browser support. The following have been tested on Minefield and Chrome.
Code is available using bzr checkout http://interreality.org/bzroot/jsvos/
Works on Minefield (Firefox nightly build) and Chrome nightly build
Works on Minefield (Firefox nightly build) and Chrome nightly build
Works on Chrome nightly build only. Minefield does not yet support Websockets. Will make an outgoing connection to interreality.org.