WebSockets

To avoid polling, we need a full-duplex solution, where the server can communicate directly with the client without the latter's initiative. Today, perhaps the most advanced and prevalent solution for this is the WebSocket protocol. A WebSocket protocol is a direct, two-way connection between the client and the server over the TCP protocol. It is structured in a way that allows both sides of the connection to initiate data transfer on their own. WebSockets were standardized in 2011 and are supported in all major browsers.