It depends. Clearly
the 'X' in AJAX stands for XML, but
several AJAX proponents are quick to point out that
nothing in AJAX, per se, precludes using other types of
* XML - Web Services and AJAX seem made for one another.
You can use client-side API's for downloading and
parsing the XML content from RESTful Web Services.
(However be mindful with some SOAP based Web Services
architectures the payloads can get quite large and
complex, and therefore may be inappropriate with AJAX techniqes.)
* Plain Text - In this case server-generated text may be
injected into a document or evaluated by client-side
case with the exception that a server-side component
function you can then create the objects on the client.
object based data exchange specification, relies on this
* HTML - Injecting server-generated HTML fragments
directly into a document is generally a very effective
AJAX technique. However, it can be complicated keeping
the server-side component in sync with what is displayed
on the client.
Mashup is a popular term for creating a completely new
web application by combining the content from disparate
Web Services and other online API's. A good example of a
mashup is housingmaps.com which graphically combines
housing want-ads from craiglist.org and maps from