Install libjs-sockjs by entering the following commands in the terminal:
sudo apt update sudo apt install libjs-sockjs
Description:
WebSocket emulation - Javascript client
SockJS 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. . Under the hood SockJS tries to use native WebSockets first. If that fails it can use a variety of browser-specific transport protocols and presents them through WebSocket-like abstractions. . SockJS is intended to work for all modern browsers and in environments which don't support WebSocket protocol, for example behind restrictive corporate proxies.
Homepage: https://github.com/sockjs/sockjs-client
Version: 0.3.4+dfsg-2
Section: universe/web