The first approach was to create a screen-based system with very rich interactions using a sophisticated, powerful technology such as Java or Flash.

The alternative approach was to create a page-based system using easier-to-learn core web standards like XHTML and CSS whose more basic capabilities force less-rich interactions.

A new technological approach, dubbed Ajax, might just be the right mix between the two.

Ajax is a new web technology that marries the benefits of both screen and paged-based approaches. By allowing more sophisticated functionality using easier-to-implement web standards, Ajax is proving a real alternative for creating powerful web applications.

Ajax applications, on the other hand, don't need to refresh the entire page to update information on it. Instead, Ajax apps can simply update parts of the page at any time, giving users an instantaneous response to their inputs and queries. This allows users to continually see what they're working on and react to any changes, errors, or updates the interface notifies them of.

Single Screen Interface
One of the biggest reasons to use the screen-based approach is the simplicity of a single-screen interface. In User Interface Engineering's reports on Flash, we found that single screen interfaces proved very useful for people, providing several advantages over page-based applications.

One advantage of a single-screen is that users can see the big picture of the application, seeing all of the steps necessary to complete the application. This gives users a clear idea of what is expected of them during a transaction.

On a page-based application, they might have to click through several pages without knowing what is ahead of them.