Java Reference
In-Depth Information
C
HAPTER
10: W
ORKING
WITH
AJAX S
ITES
• Understanding AJAX
• Understanding the Components of AJAX
• Parsing XML
• Generating XML
AJAX (Asynchronous JavaScript and XML ) is a web development technology that has
become very popular. AJAX web sites look much more like traditional GUI applications, than
they do regular web sites. When you access a regular web site, you move from one web page
to another, as you use the web site. AJAX applications usually use a single page, and update
only what needs to be updated.
In an attempt to respond quicker to the user and behave more like traditional applica-
tions, AJAX web applications attempt to limit movement from one web page to another. Your
browser's URL line stays the same, and only the part of the page that actually changed is
updated. There are many commercial websites that make use of AJAX, such as:
• Google
• Digg
• Yahoo Mail
• Writely
There are still HTTP requests and responses being transmitted between the web brows-
er and web server; however, the HTTP responses do not move the user to a new page. Rather,
JavaScript interprets these HTTP responses on the web browser. This allows for much more
real-time interaction with the user.
AJAX is an acronym for Asynchronous JavaScript and XML. As implied by the name,
AJAX employs a number of existing web technologies. Because AJAX is based on existing
web technologies, AJAX works on nearly every web browser. Table 10.1 summarizes the
technologies used by AJAX.
