The WebSocket protocol provides a way of creating web applications that support two-way communication between clients and servers. Designed to work well with the existing web infrastructure, the WebSocket holds a design principle where the connection initiates its life as an HTTP connection allowing full backward compatibility with non-WebSocket technology. The protocol switch from HTTP to WebSocket is referred to as the WebSocket handshake. One of the unique features WebSockets provide is its ability to traverse firewalls and proxies, a problem area for many applications.
WebSocket is supported by leading web browsers including Chrome, Firefox, Internet Explorer, Opera, and Safari, and more and more server application frameworks are now supporting WebSocket as well.