| This book is dedicated to making web applications look and act like desktop applications that run on your computer. As we advance into the Internet Age, the difference between the desktop and the Internet is going to keep diminishing. One issue that up until now has divided desktop applications from browser-based applications is that in the browser, you usually have to wait for the whole page to refresh before you see any results. Want to buy a book online? Click the book and –flash– the shopping cart page appears. Want to check out? Click the checkout button and –flash– that page appears. Then it’s on to –flash– the credit card information page.
All that flashing gives online applications a very different feel from that of applications on your computer. The idea behind Ajax is to get rid of all the flashing page refreshes that plague the online experience. With Ajax, you can connect to a web server behind the scenes, download data, and then display that data in the current page in a browser, all without refreshing the page.
That’s the future of web development—creating a browsing experience that is no different from using a program on your own computer. Ajax enables you create that browsing experience.
This book gives you a complete introduction to Ajax—everything you need to know is here. We’ll start with an overview of what Ajax can do, and how it’s being used today. Then, you’ll get an introduction to JavaScript, which is the foundation of Ajax on the browser side of the equation (later on, you’ll see the web server side). After you have JavaScript under your belt, we’ll dig into Ajax itself, showing you how to create Ajax-enabled applications. We’ll also take a look at some special problems, such as how to keep two Ajax requests to the server from getting confused with each other. |