WebSockets

WebSocket is a protocol that allows for a persistent TCP connection between server and client so they can exchange data at any time.

Any client or server application can use WebSocket, but principally web browsers and web servers. Through WebSocket, servers can pass data to a client without prior client request, allowing for dynamic content updates.

• Websocket on Wikipedia
• WebSocket reference on MDN
• Writing WebSocket client applications
• Writing WebSocket servers