wohugb/index.html

## index.html
<html>
  <body>
    <h4>websocket</h4>
    <h5>Group: <span id="group">darwin</span></h5>
    <!-- a hardoced group name -->
    <button onclick="bjoin();">join group</button><br />
    <input id="text" type="text" />
    <span id="out"></span>
    <script>
      var group = document.getElementById("group").textContent;

      var ws = new WebSocket("ws://localhost:5000");
      ws.onerror = function (e) {
        out.innerHTML = e;
      };
      ws.onclose = function (e) {
        out.innerHTML = "closed" + e;
      };
      ws.onopen = function () {
        out.innerHTML = "connected ";
      };
      ws.onmessage = function (ms) {
        out.innerHTML += ms.data + "<br>";
      };
      function send(msg) {
        ws.send(JSON.stringify({ msg: msg }));
      }
      function broadcast(msg, room) {
        ws.send(JSON.stringify({ room: room, msg: msg }));
      }
      function join(room) {
        ws.send(JSON.stringify({ join: room }));
      }
      function bjoin() {
        //alert(group);
        join(group);
      }
      text.onchange = function (el) {
        //alert(el.target.value);
        broadcast(el.target.value, group);
      };
    </script>
  </body>
</html>

## server.js
const WebSocket = require('ws');
const http = require('http');

const express = require('express');
const app = express();

app.use(express.static('public'));
const bserver = http.createServer(app);
const webPort = 5000;

bserver.listen(webPort, function () {
  console.log('Web server start. http://localhost:' + webPort);
});
const wss = new WebSocket.Server({ server: bserver });

wss.on('connection', ws => {
  ws.room = [];
  ws.send(JSON.stringify({ msg: "user joined" }));
  console.log('connected');
  ws.on('message', message => {
    console.log('message: ', message);
    //try{
    var messag = JSON.parse(message);
    //}catch(e){console.log(e)}
    if (messag.join) { ws.room.push(messag.join) }
    if (messag.room) { broadcast(message); }
    if (messag.msg) { console.log('message: ', messag.msg) }
  })
  ws.on('error', e => console.log(e))
  ws.on('close', (e) => console.log('websocket closed' + e))
})

function broadcast(message) {
  wss.clients.forEach(client => {
    if (client.room.indexOf(JSON.parse(message).room) > -1) {
      client.send(message)
    }
  })
}
	<html>
	<body>
	<h4>websocket</h4>
	<h5>Group: <span id="group">darwin</span></h5>
	<!-- a hardoced group name -->
	<button onclick="bjoin();">join group</button><br />
	<input id="text" type="text" />
	<span id="out"></span>
	<script>
	var group = document.getElementById("group").textContent;

	var ws = new WebSocket("ws://localhost:5000");
	ws.onerror = function (e) {
	out.innerHTML = e;
	};
	ws.onclose = function (e) {
	out.innerHTML = "closed" + e;
	};
	ws.onopen = function () {
	out.innerHTML = "connected ";
	};
	ws.onmessage = function (ms) {
	out.innerHTML += ms.data + "<br>";
	};
	function send(msg) {
	ws.send(JSON.stringify({ msg: msg }));
	}
	function broadcast(msg, room) {
	ws.send(JSON.stringify({ room: room, msg: msg }));
	}
	function join(room) {
	ws.send(JSON.stringify({ join: room }));
	}
	function bjoin() {
	//alert(group);
	join(group);
	}
	text.onchange = function (el) {
	//alert(el.target.value);
	broadcast(el.target.value, group);
	};
	</script>
	</body>
	</html>
	const WebSocket = require('ws');
	const http = require('http');

	const express = require('express');
	const app = express();

	app.use(express.static('public'));
	const bserver = http.createServer(app);
	const webPort = 5000;

	bserver.listen(webPort, function () {
	console.log('Web server start. http://localhost:' + webPort);
	});
	const wss = new WebSocket.Server({ server: bserver });

	wss.on('connection', ws => {
	ws.room = [];
	ws.send(JSON.stringify({ msg: "user joined" }));
	console.log('connected');
	ws.on('message', message => {
	console.log('message: ', message);
	//try{
	var messag = JSON.parse(message);
	//}catch(e){console.log(e)}
	if (messag.join) { ws.room.push(messag.join) }
	if (messag.room) { broadcast(message); }
	if (messag.msg) { console.log('message: ', messag.msg) }
	})
	ws.on('error', e => console.log(e))
	ws.on('close', (e) => console.log('websocket closed' + e))
	})

	function broadcast(message) {
	wss.clients.forEach(client => {
	if (client.room.indexOf(JSON.parse(message).room) > -1) {
	client.send(message)
	}
	})
	}