Node.js code must be run by the node process, not the browser (the code must run in the server).
To run the code, you must run the command:
node server.js
And then you can access your server from a browser by typing “http://localhost:8080”, for example. You must have a file server.js (or whatever) with the server code you want (in this case, creating a web server in port 8080).
You can follow this easy example, using express as http server module: http://expressjs.com/starter/hello-world.html