Справочник Пользователя для Wiley ASP.NET AJAX Programmer's Reference: with ASP.NET 2.0 or ASP.NET 3.5 978-0-470-10998-4
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978-0-470-10998-4
AJAX Technologies
Traditional Web pages use server-side technologies and resources to operate and deliver their
features and services to end users. These Web pages require end users to perform full-page
postbacks to the server, where these pages can run the required server-side code to deliver the
requested service or feature. In other words, these Web pages use the click-and-wait, user-
unfriendly interaction pattern, which is characterized by waiting periods that disrupt user
workflow and degrade the user experience. This click-and-wait user interaction pattern is what
makes the traditional Web applications act and feel very different from their desktop counterparts.
features and services to end users. These Web pages require end users to perform full-page
postbacks to the server, where these pages can run the required server-side code to deliver the
requested service or feature. In other words, these Web pages use the click-and-wait, user-
unfriendly interaction pattern, which is characterized by waiting periods that disrupt user
workflow and degrade the user experience. This click-and-wait user interaction pattern is what
makes the traditional Web applications act and feel very different from their desktop counterparts.
Asynchronous JavaScript And XML (abbreviated AJAX ) is a popular Web application development
approach that uses client-side technologies such as HTML, XHTML, CSS, DOM, XML, XSLT,
Javascript, and asynchronous client-callback techniques such as
approach that uses client-side technologies such as HTML, XHTML, CSS, DOM, XML, XSLT,
Javascript, and asynchronous client-callback techniques such as
XMLHttp
requests and hidden-frame
techniques to develop more sophisticated and responsive Web applications that break free from the
click-and-wait pattern and, consequently, act and feel more like a desktop application. In other
words, AJAX is closing the gap between Web applications and their desktop counterparts.
click-and-wait pattern and, consequently, act and feel more like a desktop application. In other
words, AJAX is closing the gap between Web applications and their desktop counterparts.
This chapter begins by discussing the main characteristics of AJAX-enabled Web pages in the con-
text of an example.
text of an example.
Google Suggest
The Google Suggest Web page (
www.google.com/webhp?complete=1
) contains an AJAX-enabled
search box that completes your search items as you type them in, as shown in Figure 1-1 . Under
the hood, this AJAX-enabled search box uses AJAX techniques to asynchronously download the
required data from the Web server and to display them to the end user without interrupting the
user’s interaction with the page. All the client-server communications are performed in the back-
ground as the end user types into the search box.
the hood, this AJAX-enabled search box uses AJAX techniques to asynchronously download the
required data from the Web server and to display them to the end user without interrupting the
user’s interaction with the page. All the client-server communications are performed in the back-
ground as the end user types into the search box.
An AJAX-enabled component such as the Google Suggest search box exhibits the following four
important characteristics:
important characteristics:
❑
It uses HTML, XHTML, CSS, DOM, and JavaScript client-side technologies to implement
most of its functionalities where the code runs locally on the client machine to achieve the
most of its functionalities where the code runs locally on the client machine to achieve the
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