WebSockets

WebSocket is a technology providing for bi-directional, full-duplex communications channels, over a single Transmission Control Protocol (TCP) socket, primarily in web browsers and web servers, but it can be used by any client or server application.

The WebSocket API is currently being standardized by the W3C, and the WebSocket protocol has been standardized by the IETF as RFC 6455. Because ordinary TCP connections to port numbers other than 80 are frequently blocked by administrators outside of home environments, it can be used as a way to overcome these restrictions.

WebSocket has been implemented in Firefox, Google Chrome, Opera, and Safari, as well as the mobile version of Safari in iOS 4.2. Internet Explorer 10 is expected to support WebSockets.

When a browser sends a request to the server – with WebSockets, rather than the server responding with data it may not have, it essentially keeps the connection open until the fresh, up-to-date data is ready to be sent.

WebSocket is considered by many to be the next generation of AJAX communication.