consider having a general handler so...

[katkelemen]

instead of this bit

else if (url === '/main.css') {
      res.writeHead(200, {'Content-Type' : 'text/css'});
      res.end(indexStyle);
    } else if (url === '/main.js') {
      res.writeHead(200, {'Content-Type' : 'text/js'});
      res.end(indexJS);
    } else if (url === '/cookie.js') {
        res.writeHead(200, {'Content-Type' : 'text/js'});
        res.end(cookieJS);

you could just use something like this:

else {
                fs.readFile(__dirname + '/public' + req.url, function(err, file) {
                    if (err) {
                        res.writeHead(404);
                        res.end('arm broken');
                    } else {
                        var ext = req.url.split('.')[1];
                        res.writeHead(200, {
                            'Content-Type': 'text/' + ext
                        });
                        res.end(file);
                    }
                });
            }