How to serve external js file to node.js server -

can me downloaded js file socket.io browser client.and put on js folder...but having problem node.js doesn't serves me external js

<script src="./js/socketio.js"></script> 

how serve external js file ?

here app.js server code

var app = require('http').createserver(handler) var io = require('socket.io')(app); var fs = require('fs');  app.listen(8080);  function handler (req, res) {     fs.readfile(__dirname + '/index.html',         function (err, data) {             if (err) {                 res.writehead(500);                 return res.end('error loading index.html');             }              res.writehead(200);             res.end(data);         });   }  io.on('connection', function (socket) {     socket.emit('news', { hello: 'world' });     socket.on('my other event', function (data) {         console.log(data);     }); }); 

thank in advance.