Datasheet

Chapter 1: AJAX Technologies

same response time as its desktop counterpart. This allows an AJAX-enabled component to

break free from the click-and-wait user-interaction pattern.

❑ It uses asynchronous client-callback techniques such as XMLHttpRequest to communicate with

the server. The main goal of this asynchronous communication model is to ensure that the com-

munication with the server doesn’t interrupt what the user is doing. This asynchronous commu-

nication model is another step that allows an AJAX-enabled component to break free from the

click-and-wait pattern.

❑ AJAX-enabled components normally send data to and receive data from the server in either XML

or JSON format (discussed in detail later in this chapter). This characteristic enables the client-

side code to exchange data with any type of server-side code, and vice versa, because almost all

platforms have built-in support for reading, writing, and manipulating XML or JSON data.

❑ The asynchronous communication between the client-side code and the server-side code are

normally governed by AJAX communication patterns. These patterns enable AJAX components

to take full advantage of the asynchronous nature of the communication between the client-side

code and the server-side code to determine the best time for uploading the data to or download-

ing the data from the server so the data exchange with the server won’t interrupt the user work-

flow and degrade the user experience.

In a traditional Web page, the end users trigger synchronous communications with the Web server, and

they then have to wait until the required data is downloaded from the server and the entire page is

Figure 1-1

c01.indd 2c01.indd 2 8/20/07 5:40:02 PM8/20/07 5:40:02 PM