Chat with socket.io

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Socket.IO enables real-time bidirectional event-based communication.
It works on every platform, browser or device, focusing equally on reliability and speed.

 Node 
======

Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient.

1. Install Node.js
(Choose recommended version)


https://nodejs.org/en/


2. Open cmd prompt from windows

and type npm



3. Create a directory called as testapp in c drive 


and open again cmd

Type cd c:\

then cd testapp



5. Now we will install express and socket io


npm install socketio

 then

 npm install express




6. We will create package.json in testapp folder

type
npm init


 I can edit or press enter for default values.


Then type yes

Create a file inside testapp

 index.js
=======


var app = require('express')();
var server = app.listen(8080,'localhost');
var io = require('socket.io').listen(server);


app.get('/', function(req, res){
  res.sendFile(__dirname + '/index.html');
});

io.on('connection', function(socket){
  socket.on('chat message', function(msg){
    io.emit('chat message', msg);
  });
});


and html file



index.html
========
<!doctype html>
<html>
  <head>
    <title>Socket.IO chat</title>
    <style>
      * { margin: 0; padding: 0; box-sizing: border-box; }
      body { font: 13px Helvetica, Arial; }
      form { background: #000; padding: 3px; position: fixed; bottom: 0; width: 100%; }
      form input { border: 0; padding: 10px; width: 90%; margin-right: .5%; }
      form button { width: 9%; background: rgb(130, 224, 255); border: none; padding: 10px; }
      #messages { list-style-type: none; margin: 0; padding: 0; }
      #messages li { padding: 5px 10px; }
      #messages li:nth-child(odd) { background: #eee; }
    </style>
  </head>
  <body>
    <ul id="messages"></ul>
    <form action="">
      <input id="m" autocomplete="off" /><button>Send</button>
    </form>
    <script src="https://cdn.socket.io/socket.io-1.2.0.js"></script>
    <script src="http://localhost:8080/socket.io/socket.io.js"></script>
    <script src="http://code.jquery.com/jquery-1.11.1.js"></script>
    <script>
      var socket = io.connect('http://localhost:8080');
      $('form').submit(function(){
        socket.emit('chat message', $('#m').val());
        $('#m').val('');
        return false;
      });
      socket.on('chat message', function(msg){
        $('#messages').append($('<li>').text(msg));
      });
    </script>
  </body>
</html>

Here socket.emit allows you to emit custom events on the server and client

-----------------------------------------------------------------------------
We are done.

Now in cmd prompt
type  node index.js

do not close... it starts the server

now open html in browser


For more about socket.io
https://www.tutorialspoint.com/socket.io/index.html

About Express
http://expressjs.com/