HTML5 WebSocket实现了服务器与浏览器的双向通讯，双向通讯使服务器消息推送开发更加简单，最常见的就是即时通讯和对信息实时性要求比较高的应用。以前的服务器消息推送大部分采用的都是“轮询”和“长连接”技术，这两中技术都会对服务器产生相当大的开销，而且实时性不是特别高。WebSocket技术对只会产生很小的开销，并且实时性特别高-HTML 5 WebSocket server and browser of two-way communication, two-way communication message the server push development is more simple, the most common is the im and the application of real-time demand information is higher.Before the server message push most used are　polling　and　long connection　technology, both in technology will produce considerable overhead to the server, and real-time performance is not particularly high.WebSocket technology to produce only small fraction of overhead, and particularly high real time capability