The crucial differences between pre-HTML5 communication methods and HTML5
WebSocket are located in the new HTML5 protocol. WebSocket protocol uses HTTP to
establish a connection, but the subsequent communication is performed by the
WebSocket reader protocol. In addition, the feature header is very small, resulting in
reduced communication overhead. Because a persistent connection is assumed, it is
possible for clients and servers to remain in a connected state. Accordingly, it is
necessary to update existing TCP servers to meet the new WebSocket specification.
WebSockets are present in a variety of servers. These servers may be implemented in