408 Part II: Developing an Ajax Library^
provide some Ajax facilities to those who can handle it, but simply just not require it? The
user will have a more pleasing or powerful experience with Ajax-enabled technologies
available, but they will not be locked out from the site or application without it either. The
idea of starting from the most basic technologies and layering more complexity on top
based upon user capabilities is called progressive enhancement.
If we approach design from the Ajax-required or at least highly recommended point of
view, we believe that the site or application functionality and experience really is best with
the latest technology. However, acknowledging the simple fact that ideal conditions do not
always prevail, we might opt to reduce functionality in some situations at least to some
acceptable level or at the very least fail with useful information. Starting from complexity
and reducing or failing well is typically termed graceful degradation.
To illustrate the range of choices and what end of the spectrum we start from, first
consider the range of presentation we might enjoy online.Such a range would also hold for the technology used to implement such a look.