Developing AJAX applications that preserve standard browser capabilities

Summary

Ajax applications have been widely praised for their richness of functionality, interactivity, and rapid responsiveness. Instead of loading new pages, it can dynamically load data using the XMLHttpRequest object. While it's hype and excitement for many people, there are comments that Ajax applications have lost some of the key features of the browser, including support for the back forward button.

This article will first explain why you won't be able to run in an AJAX application unless you explicitly build the back/forward buttons and other browser features. Then, we'll briefly explain how developers can address these issues. Finally, we'll see details on how the Backbase Ajax engine supports the back/forward buttons and other standard browser features.

Does the AJAX application need a back button?

Ajax promises to enable developers to create visually appealing, highly interactive Web applications based entirely on standard Web browser technologies (usually DHTML).

Previously, developers had to choose between a feature-rich (highly interactive, compelling user interface) and an easy to reach (a front-end that works under all Web browsers without requiring a client installation). Ajax applications should be able to produce both "feature-rich" and "easy to reach" front-end.

But how can an interface be considered "functionally rich" and how is an application "easy to arrive"?

It's hard to define the meaning of "feature-rich" precisely, but it's easy to intuitively realize that when you see an interface, you know it's not a feature-rich one. Desktop applications like Microsoft Office are feature-rich. The feature-rich interface uses advanced UI controls such as tabs and context menus. Such an interface provides some advanced interaction methods. For example, drag-and-drop, highlight UI elements for attention, and so on. Traditional browser applications are not feature-rich. They are limited to simple controls such as forms, and the interaction consists primarily of clicking links to new pages. Just look at Microsoft's email client to see the difference between rich and functional: Outlook is functional, and Hotmail is not very functional.

Ajax applications have been widely praised for their rich functionality. Google's Gmail is one of the most representative examples. Other Ajax apps Google has developed (Google suggest, Google Map), Microsoft's upcoming web mail client named "Kahuna" and Backbase RSS reader include advanced controls and interactive modules. Check out Dan Grossman's top Ajax applications list, which gives a list of impressive feature-rich interfaces.

From the previous discussion, it can be said that Ajax applications clearly meet the "feature-rich" standard. So is it "easy to arrive"?

First of all, the most basic is that only the interface in the Web browser to run the application is "easy to reach." Ajax applications are browser-based, so they can be accessed through a Web browser.

However, it is not enough to access the Web browser alone. Jakob Nielson in his 2000 article, flash:99% Bad, that Flash "broke the basic web interaction." End users want to be faced with a particular interaction when using a Web application. Applications need to conform to traditional web interactions and provide the following available features:

The back and Forward buttons work correctly so that end users can navigate to the history page. Users should be able to create bookmarks. Support for deep links to ensure that end users can send this page to friends and colleagues by e-mail. The refresh button works correctly to refresh the current state instead of reinitialize the application. Developers can use "view source" to see source code. The end user can use Find to search the page. Search engines can index pages and create deep links to search items.

Looking at the top AJAX applications list, we can see that most of the AJAX applications discussed earlier did break the standard way of web interaction. In the next section, we'll discuss why many AJAX applications do this.