As the Web grows and evolves, so do the expectations of the Web user. When the first
Web browser was developed, it was created to provide a relatively simple way to allow
hyperlinking between documents. Then these early browsers were coupled with the
cross-machine protocols encompassing the Internet, and suddenly documents stored on
computer servers anywhere in the world could be hyperlinked to each other.
Over time, the people who were using the Internet changed—the user base expanded
from a small group of people associated with universities and computational research to
encompass the general population. And what had been an acceptable user interface for
experts in the field was greatly lacking for commercial applications. People now want
high-quality user interfaces that are simple to use—and as more types of information,
including many kinds of media files, are available on the Internet, it becomes more difficult
to satisfy users’ expectations about how easy it should be to access the information
The need to supply users with sophisticated methods of accessing Internet resources that
were easy to use led to advanced application technologies. One type of technology, for
example, created “plug-in” browser tools that allowed the browser to use some of the
user’s local computational horsepower.
ActiveX controls, Java Applets, and Flash applications are examples of plug-in
introduced to develop new and exciting user interfaces that benefit from immediate
partial updates. Using AJAX, the browser’s screen area doesn’t flash or lock up since the
need for full-page refreshes is reduced.
Although AJAX provides technology to enable developers to build Web sites that
contain more complex content and are more dynamic than HTML alone could provide,
AJAX does have its limitations. For example, it allows asynchronous communication with
the server, which means that applications can update themselves using background
threads, eliminating the screen flicker so often seen with complex Web user interfaces.
But AJAX is strictly a browser-to-server communications mechanism. It lacks graphics,
animation, video, and other capabilities that are necessary to provide for truly
multimedia user interfaces.