GWT Basics: AJAX Programming with Java

By Michael J. Ross
2008-03-10


Introduction

Prior to JavaScript and other client-side languages, Web browsers operated as if they were HTML dumb terminals, merely presenting Web pages generated on a server. For such pages, every user action requires a full page refresh, with a round-trip over the Internet, which degrades performance and thus user satisfaction. It may be fine for a great many Web sites, but it is completely inadequate for high-performance dynamic Web applications. Even e-commerce sites using wholesale page refreshes every time, find that users can encounter all kinds of problems. For instance, e-commerce sites often exhort customers to not use their browser's Back button while shopping online, and to not click the Submit button twice should the purchase page fail to respond. But what if the network hangs and customer does not know if the purchase went through?

Traditional use of JavaScript made it possible to embed functionality on the client-side, with far superior speed, by eliminating network traffic. It was — and continues to be — ideal for such needs as user form validation. But such JavaScript code does not communicate with the server, and thus has no way of accessing application data from a database, or even maintaining state in between page refreshes.

Tutorial Pages:
» Introduction
» AJAX Overview
» GWT to the Rescue
» Installing GWT
» Running Sample Applications
» Resources

Related Tutorials: » AJAX Accessibility for Websites » AJAX and PHP Form Processing » The obligatory 'My Ajax Tutorial' Post » A Designer's Guide to Prototyping Ajax » Ajax Wireframing Approaches