WebSockets is an advanced technology that makes it possible to open an interactive communication session between the user's browser and a server. With this API, you can send messages to a server and receive event-driven responses without having to poll the server for a reply.
Using WebSockets
Here will be a list of articles on how to use WebSockets, including examples.
WebSocket interfaces
Listing of the interfaces; divided by category if appropriate.
Specifications
Spec table here
Browser compatibility
Compatibility table.
See also
Other useful information.