Node JS - How to use URL query strings?

How can you use URL query strings in NodeJS like PHP's $_GET["query"] command?

http://php.net/manual/en/reserved.variables.get.php

Say for example you wanted to extend the code below to use a ?option=1 on the /page001 part.

So visiting ServerURL/page001?option=1 would write "Page1: Option 001 Selected".

And ServerURL/page001?option=2 would write "Page1: Option 002 Selected" etc.

var http = require('http');
var fs = require("fs");
var location = require('location-href');

var HttpDispatcher = require('httpdispatcher');
var dispatcher = new HttpDispatcher();

////////////////////

var http=require('http');
var url=require('url');

var server=http.createServer(function(req,res){
    var pathname=url.parse(req.url).pathname;
    switch(pathname){
        case '/page001':
            res.end('<div id="page001"><h2>Page 001</h2><div>Page 001 Content</div></div>');
            console.log("Page 001 Loaded");
        break;
        case '/page002':
            res.end('<div id="page002"><h2>Page 002</h2><div>Page 002 Content</div></div>');
            console.log("Page 002 Loaded");
        break;
        default:
            res.end('<div id="default"><h2>Default</h2><div>This is the default page</div></div>');
            console.log("Default page was loaded");
        break;
    }

}).listen(8080);

console.log("Running on Port 8080");