Tuesday, April 04, 2006


As the Internet has become
more mature, rich applications
featuring responsive
user interfaces and interactive
capabilities have become
increasingly popular. The capabilities
represent a way to make programs
easier to use and more functional, thus
enhancing the user experience.
Developers have used a variety of
applications from companies such as
Macromedia, Microsoft, and Sun
Microsystems to add these capabilities
in the past, as discussed in the
“Developing Large-Scale Rich Web
Applications” sidebar.
However, Web applications have generally
exhibited problems such as slow
performance and limited interactivity,
particularly when compared to typical
desktop applications, noted Nate Root,
research director for Forrester Research,
a market analysis firm.
Now, developers are going back to
the future by building Web applications
using Ajax (Asynchronous JavaScript
and XML), a set of technologies mostly
developed in the 1990s. A key advantage
of Ajax applications is that they
look and act more like desktop applications,
according to Root.
Proponents argue that Ajax applications
perform better than traditional
Web programs. As an example, Ajax
applications can add or retrieve new
data for a page it is working with and
the page will update immediately without
reloading. For instance, when users
hold down the left mouse button and
slide the cursor over an image on the
Ajax-based Google Maps beta site
(http://maps.google.com) to retrieve a
part of the map not shown on the
screen, the updates occur smoothly
and the image appears to move and
change immediately. With typical Web
applications, users must spend time
waiting for entire pages to reload, even
for small changes.
When companies began working
with the technology several years ago,
before the approach even had the name
Ajax, they used it for smaller, less
important applications. However, as
the component technologies have
improved, Google and a number of
other companies have started using
Ajax for more important enterprise
In addition to its map site, Google
has worked with Ajax to build applications
such as Gmail and Google
Groups, a community and discussion
service, said Bret Taylor, Google Maps
product manager.
Flickr uses Ajax in some parts of its
Web site, on which users post and
share photographs. For example, Ajax
enables the site to let users add and
view photo annotations. Expedia has
produced features such as pop-up calendars
on its travel site via Ajax.
All major browsers now support the
technology. Thus, Ajax could pose a
threat to Microsoft, Macromedia, and
Sun. However, while some companies
may decide Ajax is particularly useful
for certain kinds of applications, industry
observers say it won’t be suitable
for all types. And in some cases, companies
may use Ajax to complement
other Web-application approaches.
Meanwhile, Ajax still faces several
technical challenges, such as usage
complexity and security.

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