Asp.Net Ajax Tutorials Overview

Welcome to Asp.Net Ajax Tutorials. The objective of these tutorials is to provide in depth understanding of Asp.Net Ajax concepts. In these tutorials, we will cover topics such as Architecture, Ajax Components, Ajax Control Tool Kit, Ajax Extenders etc.

In addition to Ajax Tutorials, we will cover common interview question and issues in Ajax.


AJAX(Asynchronous JavaScript and XML)

In traditional website which was developed without using AJAX, the following drawbacks are as follows.

When post back occurs then entire page will be submitted to server including the data related to advertisements displayed on that page. Because of this the amount of data to transfer between client and server will increase that effects the performance of the application.

User must wait until entire page is loaded from server and he can’t interact with the page until entire page is loaded.

Main purpose of AJAX is to develop rich interactive applications and increase performance of the applications. Ajax based web-applications have following advantages compared to the traditional websites developed without using AJAX

With Ajax you can submit only a part of the page to server without submitting the entire page. Which will reduce the amount of data to be transformed between client and server and which will increase the performance of the application.

While a part of the page is updated from the server user or interact with the remaining page without causing another post back, without waiting until that particular part of the page is updated from the server.

With AJAX communication with server will be Asynchronous, because which user can interact with the page while the page is updated from the server.

Ajax Components

AJAX contains the following important components.


Xml HTTP is used for Asynchronous communication between client  & web server which  is not possible with HTTP.


major part of AJAX is JavaScript  and Microsoft provides pre-defined JavaScript libraries with in AJAX to send data from client to server. and server to client with the help of XMLHTTP.

DHTML & DOM (Document object mode)

These two components are used to dynamically update a particular part of the page.


These two are the data formatters used by AJAX for transforming the data between client and server Asynchronously.

AJAX is not completely client side technology or completely server side technology and it must be available both on client and server for asynchronous communication between client and server.

AJAX is Built into .Net framework and visual from the version 3.5 and visual 2008 with the AJAX Built into visual you will get only 5 controls and all the remaining controls of Ajax are provided as AJAX control tool kit, which you have to download and install from internet. The basic controls of the AJAX provided with visual are as follows.

All the basic AJAX controls provided with visual are available within AJAX extensions tab in the Toolbox and those controls and their purpose are as follows.

AJAX Control Toolkit website, All the controls developed using AJAX features are provided as AJAX control Toolkit. But these control are not included in visual because they are provided as open source and any new features & controls added to it can be downloaded from the website to get latest features of the AJAX control Toolkit you can download AJAX control Toolkit from the website This is available as a Zip file & after download if extract it to your folder to get Ajax control Toolkit.dll

Adding AJAX control Toolkit to Toolbox

To add all the controls of AJAX control Toolkit to the Toolbox, Right click on the Toolbox and  choose “new tab” that creates a new Tab in the Toolbox and set its caption as ‘AJAX control’ Toolkit. Now right click with in this newly created Tab and choose “ Choose Items ” that opens choose items dialog box. within this dialogbox, click on the browse button available at the bottom Right corner and within the Browse dialog box select AJAX control Toolkit.dll file from the folder to which you extracted Ajax control toolkit Zip file and than click on open button followed by ok button.

Within AJAX control Toolkit a control called ‘Toolkit script manager’ is provided & this control must be placed an the page while using AJAX control Toolkit controls on the webpage. In old versions of AJAX control Toolkit there is no separate script manager & the script manager provided with AJAX extensions itself is used for AJAX control Toolkit also.