Until the original poster gives us more info, you can read the source here: http://multiplayerchess.com/mpc.js

NodeJS and CouchDB. Mustache (http://mustache.github.com) for templating, Jeff Hlywa's chess.js for move validation and JSBuild (http://jsbuild.kodfabrik.com) for the compile of CommonJS modules for browsers, and excanvas for cross-browser canvas