AJAX - Asynchronous Javascript And XML

AJAX is used to create applications with improved responsiveness:

With Ajax, we are able to do away with the traditional "Click-and-Wait" Web-application architecture (like g-mail), enabling us to provide the responsiveness and interactivity users expect from desktop.

Using AJAX enhances the user experience and the application performance by having

• Partial Page Refresh
• Substantially Improved Response Time
• Fewer Clicks
• Drag and Drop etc

Used in medium to very large sized projects.

The N-tier architecture gives the following benefits:

• The application is divided into logically isolated pieces reducing tight coupling between the UI, business processes and database.
• Change in the underlying database and data access methods do not have any effect on the presentation layer or client application.
• It becomes easier to modify or extend the applications, without breaking or recompiling the client-side code.
• The business logic object can be used by multiple user interfaces.

• To send requests to third party web services in XML format and parse the XML response and publish it in the applications.
• As a client side data store using XML Data Islands and XSLT to reduce the database access thereby improving application performance.
• Mustang XML to interchange product information in e-commerce applications.

Widgets:

• Widgets are reusable modules, which are highly independent like products but can easily communicate/integrate with other widgets.
• Widget modules are fully parameterized, so can customize their properties and functionalities without the need for re-programming
• Eliminates the need for integration testing.

Web Services

A Web Service is a library providing data and services to other applications over the Internet.  Software applications written in various programming languages and running on various platforms can use web services to exchange data over computer networks.

Internal Web Services are used to connected different parts of an organization’s internal information system, such as sales, human resources, finance and production. For example, a finance application can call a real-time EuroToUSD converter with in the organization; and a management Web Service can be used to retrieve particular sales clients from an internal database.

Another example is an “AutoSuggest” textbox (like Google Suggest) in DOT NET using internal web service. When the character is type in the control, it will call a web service called “Filterlist”. This “Filterlist” web service will query the database and retrieve the relevant items to “AutoSuggest” Textbox.