Book Image

HTML5 Data and Services Cookbook

Book Image

HTML5 Data and Services Cookbook

Overview of this book

HTML5 is everywhere. From PCs to tablets to smartphones and even TVs, the web is the most ubiquitous application platform and information medium bar. Its becoming a first class citizen in established operating systems such as Microsoft Windows 8 as well as the primary platform of new operating systems such as Google Chrome OS. "HTML5 Data and Services Cookbook" contains over 100 recipes explaining how to utilize modern features and techniques when building websites or web applications. This book will help you to explore the full power of HTML5 - from number rounding to advanced graphics to real-time data binding. "HTML5 Data and Services Cookbook" starts with the display of text and related data. Then you will be guided through graphs and animated visualizations followed by input and input controls. Data serialization, validation and communication with the server as well as modern frameworks with advanced features like automatic data binding and server communication will also be covered in detail.This book covers a fast track into new libraries and features that are part of HTML5!
Table of Contents (21 chapters)
HTML5 Data and Services Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Exchanging real-time messages using WebSockets


Before HTML5 Web Sockets, web applications that needed to implement real-time updates, such as chat messages and game moves, had to resort to inefficient methods.

The most popular method was to use long polling, where a connection to the server is kept open until an event arrives. Another popular method was streaming chunked blocks of JavaScript to an iframe element, also known as comet streaming .

HTML5 WebSockets enable the exchange of real-time messages with the web server. The API is much cleaner and easier to use, less error-prone, and provides lower message latency.

In this recipe, we're going to implement a simple chat system based on WebSockets. To make the system easier to extend, we're going to use dnode on top of the underlying WebSockets. The dnode library provides full callback-based RPC for multiple languages and platforms: Node.js, Ruby, Java, and Perl. Essentially, it enables us to call server-side code as if it were executing on...