try serving http and ws from the same server.

js/babl/package.json

  "version": "0.0.0-alpha",
  "description": "a simple web-chat using websocket",
  "dependencies": {
    "ws": "0.4.31"
    "ws": "0.4.31",
    "express": "^3.5.1"
  }
}

js/babl/index.html

			function loadHistory() {
				var xhr = new XMLHttpRequest();
				xhr.open('GET', location.href + "/../msgs.json");
				xhr.open('GET', "msgs");
				xhr.onreadystatechange = function() {
					if (xhr.readyState == XMLHttpRequest.DONE) {
						var msgs = JSON.parse(xhr.responseText);

js/babl/server.js

var ws = require('ws');
var http = require('http');
var express = require('express');
var wss = new ws.Server({port: 8080});
var app = express();
app.use(express.static(__dirname + "/public"));
var server = http.createServer(app);
app.get('/msgs', function(req, res) {
	res.sendfile('msgs.json');
});
var wss = new ws.Server({server: server});
wss.broadcast = function(data) {
	var msg = typeof data === "string" ? data : JSON.stringify(data);
	}
	return name;
}
var port = parseInt(process.env.PORT || "8080");
server.listen(port);