如何在节点js服务器中连接codeigniter项目和sockets.io

Question

I am trying to implement sockets.io in my CodeIgniter project with node my server.js`File:

var express=require('express');
var app=express();
var server=require('http').createServer(app);
var io=require('socket.io').listen(server);

//connect server to port
var listener=server.listen(process.env.PORT || 80,function(){
     console.log('Listening on port ' + listener.address().port);
});

and Client side:

    <script type="text/javascript" src="assets/js/node_modules/socket.io-client/dist/socket.io.js"></script>
$(function(){
            var socket = io.connect('http://localhost');
            console.log(socket);
});

But i am getting

EIO=3&transport=polling&t=MHvYqNg 404 (Not Found)

Error what have I done wrong? Please help Thanks in advance