版本：1.5.1
- https://cdn.bootcdn.net/ajax/libs/sockjs-client/1.5.1/sockjs.js
- https://cdn.bootcdn.net/ajax/libs/sockjs-client/1.5.1/sockjs.min.js
SockJS-client is a browser JavaScript library that provides a WebSocket-like object. SockJS gives you a coherent, cross-browser, Javascript API which creates a low latency, full duplex, cross-domain communication channel between the browser and the web server.