Week-11

=Week-11=

Distinguish between a normal HTTP request and an AJAX HTTP request.
Microsoft's ASP.NET technology brings an object-oriented and event-driven programming model and unites it with the benefits of compiled code. However, its server-side processing model has several drawbacks inherent in the technology:


 * 1) Page updates require a round-trip to the server, which requires a page refresh.
 * 2) Round-trips do not persist any effects generated by Javascript or other client-side technology (such as Adobe Flash)
 * 3) During postback, browsers other than Microsoft Internet Explorer do not support automatically restoring the scroll position. And even in Internet Explorer, there is still a flicker as the page is refreshed.
 * 4) Postbacks may involve a high amount of bandwidth as the __VIEWSTATE form field may grow, especially when dealing with controls such as the GridView control or repeaters.
 * 5) There is no unified model for accessing Web Services through JavaScript or other client-side technology.

Enter Microsoft's ASP.NET AJAX extensions. AJAX, which stands for Asynchronous JavaScript And XML, is an integrated framework for providing incremental page updates via cross-platform JavaScript, composed of server-side code comprising the Microsoft AJAX Framework, and a script component called the Microsoft AJAX Script Library. The ASP.NET AJAX extensions also provide cross-platform support for accessing ASP.NET Web Services via JavaScript