HTML5 Games: Creating Fun with HTML5, CSS3 and WebGL, 2nd Edition

Chapter 13

Going Online with WebSockets

In This Chapter

• Using WebSockets for online communication

• Introduction to Node.js and server-side JavaScript

• Creating a simple chat application

IN THIS CHAPTER, I introduce you to WebSockets and Node, two relatively new technologies that make creating network applications and server-side scripting a much better experience than it has been in the past.

In the first half of the chapter, I take you through the WebSocket API and show you how to establish and manage a connection to a server as well as how to communicate with the server by sending and receiving data.

I then show you how to use Node to create server-side JavaScript applications. By the end of the chapter, you will know how to create a chat server and client using Node and WebSockets.

Using WebSockets

Traditionally, whenever network communication outside regular Ajax requests was needed, the solution was either plug-in-based or a workaround using existing XmlHttpRequest technology, possibly involving long-lived connections that wait for responses from the server. HTTP wasn't really designed with polling in mind, and HTTP requests and responses carry a lot of overhead. When all the HTTP headers, cookies, and other request data are combined, an HTTP request can easily have 1K of overhead data. That's a lot if you want to send only a short status update.

WebSockets were created to provide an alternative geared specifically toward persistent connections and low-latency communication. ...