Balancing Client and Server Programming with ASP.NET AJAX
Without the advanced use of JavaScript running in the browser, web applications
have their logic running on the server. This means a lot of page refreshes for
potentially small updates to the user’s view. With AJAX, much of the logic
surrounding user interactions can be moved to the client. This presents its own
set of challenges. Some examples of AJAX use include streaming large datasets
to the browser that are managed entirely in JavaScript. While JavaScript is a
powerful language, the debugging facilities and options for error handling are
very limited. Putting complex application logic on the client can take a lot of
time, effort, and patience. ASP.NET AJAX allows you to naturally migrate some
parts of the application processing to the client while leveraging partial page
rendering to let the server control some aspects of the page view.
Some websites make an application run entirely from a single page request, where
JavaScript and AJAX will do a great deal of work. This presents some tough
challenges. Users generally expect that the Back button will take them to the
state of the application they were just viewing, but with AJAX applications
this is not necessarily the case. The client may be sending some information to
the server for persistent state management (perhaps in server memory or a
database), but this requires extra code and special attention to error handling
and recovery.
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Book Excerpt: Developing Next-Generation Web Applications
Chapter Contents
This excerpt from
Professional ASP.NET 2.0 AJAX by Matt Gibbs, Dan Wahlin, is
printed with
permission from Wrox Publication.
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The richest, most maintainable applications seem to be those that balance client
and server resources to provide quick response times, easy access to server
resources, and a minimum of blocking operations while new page views are
fetched.
ASP.NET AJAX provides a mix of client and server programming features. The
Microsoft AJAX Library is aimed at client development. It provides a type
system for an object-oriented approach to JavaScript development. It makes it
easy to register code to respond to events. It provides useful functions to
simplify common tasks like finding elements on the page, attaching event
handlers, and accessing the server. The server features include functionality
for managing JavaScript code to be sent to the client, declaring regions of the
page to be updated asynchronously, creating timers for continuous updates, and
accessing ASP.NET services such as user profile data and authentication.
More Related links
Answer - ASP.NET Ajax Framework is used for implementing the
Ajax functionality......
Answer - Back functionality cannot work because the dynamic
pages don’t register themselves to the browsers history engine..........
Here it shows how a page controller pattern works in ASP.NET.
MVC, which stands for Model View Controller, is a design pattern that helps us
achieve the decoupling of data access and business logic from the presentation
code , and also gives us the opportunity to unit test the GUI effectively and
neatly, without worrying about GUI changes at all..........
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