main.js

var io = require("socket.io"),
http = require("http"),
url = require("url"),
path = require("path"),
fs = require("fs"),
port = process.argv[2] || 1337, //you can specify port in command line ie node main.js 8080

//create a web server
server = http.createServer(function(request, response) {

    //parse the request url for the path and grab the filename
    var uri = url.parse(request.url).pathname
    , filename = path.join(process.cwd(), uri);
  
  //if filename doesnt exist show 404
    path.exists(filename, function(exists) {
        if(!exists) {
            response.writeHead(404, {
                "Content-Type": "text/plain"
            });
            response.write("404 Not Found\n");
            response.end();
            return;
        }
    
    //read the filename
        fs.readFile(filename, "binary", function(err, file) {
            //if an error occured reading show a 500 error on the page
            if(err) {        
                response.writeHead(500, {
                    "Content-Type": "text/plain"
                });
                response.write(err + "\n");
                response.end();
                return;
            }
            //check to see if the file is a .js file
            var filematch = new RegExp(/(js$)/);
            
            //if file is a javascript file send the file content-type as javascript otherwise its sent as text/plain
            if(filename.match(filematch)){
                response.writeHead(200, {
                    "Content-Type": "text/javascript"
                });
                response.write(file, "binary");
                response.end();
            }else{
                response.writeHead(200);
                response.write(file, "binary");
                response.end();
            }
      
        });
    });
}).listen(parseInt(port, 10));

//init socket.io
var sio = io.listen(server);
sio.sockets.on("connection", function(socket){
    
    socket.on("newmessage", function(msg){
       socket.broadcast.emit("chatmessage", {
           text: msg.text,
           user: msg.user
       }) 
    });
    
    setTimeout(function() {
        socket.broadcast.emit('chatmessage', {
            text: "New user has entered chat."
        });
    }, 3000);
    
});

console.log("Chat server running at\n  => http://localhost:" + port + "/\nCTRL + C to shutdown");