Web-minecraft is minecraft client written in Javascript. From web browser this client connects to proxy that translates Websocket connection to TCP and then to real minecraft server, so you can play minecraft in the browser. Web-minecraft now only supports minecraft 1.16.5.
Live demo with no installation: https://minecraft.js.org.
npm install
npm start
This will start express and webpack in development mode: whenever you save a file, the build will be redone (it takes 2s), and you can refresh the page to get the new result.
Connect to http://localhost:8080 in your browser. Also specify correct server(1.16.5) ip in url param.