ASP.NET AJAX Introduction

AJAX is not a new programming language, but a new way to use existing standards. AJAX is the art of exchanging data with a server, and update parts of a web page – without reloading the whole page. There are too many web applications running on the web that are using AJAX technology such as gmailfacebook, twitter, google mapyoutube etc. Here we are going to discuss how ASP.NET uses AJAX under following topics.

  • ASP.NET AJAX Concepts
  • ASP.NET AJAX Architecture
  • Creating ASP.NET AJAX Application

AJAX Concepts

AJAX is an acronym for Asynchronous JavaScript and XML. This acronym was first coined by Jesse James Garrett in February 2005. The key idea behind the scene is that when a web form is normally submitted to the web server it is a synchronous full page submit. Then the user of the page can see visual feedback for that page submit and it may be an annoying thing. Instead a certain area of the web page is going to submit asynchronously and independently to the server. It is very efficient way to submit as well as get data to and from the server. This can be done through JavaScript in a manner that the Document Object Model (DOM) of the web page is accessed by JavaScript and insert data dynamically. The data exchange method of AJAX is XML. JavaScript written in AJAX is much complicated and we do not want to worry about because ASP.NET server controls are playing the major role. One most important feature from AJAX is Partial Page Updates. We can have submission of data dynamically and interactively while using the web page. Then we can see how web pages are more responsive. One other thing about AJAX is all based on open standards and cross platform. AJAX is not a Microsoft invention or acronym, it is a way of designing web pages. Different vendors have their own AJAX libraries. Microsoft presents ASP.NET AJAX as their library. This ASP.NET AJAX supports for data integration with web services, cross browser, rich user interface, integration with ASP.NET security and browser responsiveness.

ASP.NET AJAX Architecture

asp.net ajax architecture

Creating ASP.NET AJAX Application

We need ASP.NET AJAX Extensions and ASP.NET AJAX Server Controls in the Toolbox to create an AJAX enabled application.

ASP.NET AJAX Server Controls

ScriptManager

We can have one and only one ScriptManager in our web form. It manages all the scripts that are to be sent to the client. But the ScriptManager does not generate all the JavaScript that necessary. It is responsible for managing scripts that are produced by other server controls of the page.

UpdatePanel

Next most important server control is UpdatePanet and it enables the page for partial page updates. It has several properties. If we want to update a portion of a page then we need to add those portions of the page into own UpdatePanel.

UpdateProgress

This server control provides visual feedback about the progress that the partial page update is undergoing. Sometimes we need to keep waiting the user until some portion of the page is updated. For that thing UpdateProgress can be used.

Timer

This server control is used for periodic page postbacks which may be full or partial. If the timer is placed outside of an UpdatePanel a full page postback is occurred but the timer is in the UpdatePanel partial page postback is occurred. We can specify the time period in between two consecutive page updates.

You can see the implementation details of an ASP.NET AJAX enabled web application as the next post. Therefore stay tuned with us.

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