1.What is Ajax?

Ajax is abbreviated as Asynchronous Javascript and XML. It is new technique used to create better, faster and more interactive web systems or applications. Ajax uses asynchronous data transfer between the Browser and the web server.
This technique is used to make internet faster and user friendly. It is not a programming language.

2.What are Ajax applications?

Browser based applications and platform independent applications are used by Ajax.

3.How many types of triggers are present in update panel?

There are two types of triggers used in update panel:

• PostBackTrigger – This works as full postback and it cannot work asynchronously
• AsyncPostBackTrigger – Partial post back asynchronously

4.What are all the controls of Ajax?

Following are the controls of Ajax:

• ScriptManager
• ScriptManagerProxy
• UpdatePanel
• UpdateProgress
• Timer

5.What is the name of the DLL that contains Ajax control tool kit?

Ajaxcontroltoolkit.dll is the DLL used for Ajax control tool kit and it can be downloaded from the internet. It can be added in the tool box or copied directly in the bin folder.

6.What role of #&& in querystring?

# is treated as fragment delimiter to delimit the history state and && precedes is used to check on the information in the query string.

7.How to control the duration of an Ajax request?

AsyncPostBackTimeout property is used to control the duration of Ajax request. Deafult value of this property is 90 seconds.
Example –
1 <asp:ScriptManager runat=”server” id=”sample” AsyncPostBackTimeout=”40”/>

8.What are the advantages of Ajax?

Following are the advantages of Ajax:

• Bandwidth utilization – It saves memory when the data is fetched from the same page.
• More interactive
• Speeder retrieval of data

9.What are the disadvantages of Ajax?

Following are the disadvantages of Ajax:

• AJAX is dependent on Javascript. If there is some Javascript problem with the browser or in the OS, Ajax will not support
• Ajax can be problematic in Search engines as it uses Javascript for most of its parts.
• Source code written in AJAX is easily human readable. There will be some security issues in Ajax.
• Debugging is difficult
• Increases size of the requests
• Slow and unreliable network connection.
• Problem with browser back button when using AJAX enabled pages.

10.What is update panel?

Update panel is a server control used to update the specified portion of a web page. Script Manager needs to be used whenever update panel is used. Using update panel, user cannot handle outside controls.

11.Which are the two methods used for cross domain Ajax calls?

There are two methods used to transfer data between the two more more security domains:

• CROS – Cross Origin Resource Sharing and it works with the HTTP web browsers
• SONP – JSON with Padding which works with the HTTP GET and on legacy browsers

12.What are all the technologies used by Ajax?

AJAX uses following technologies:

• JavaScript
• XMLHttpRequest
• Document Object Model (DOM)
• Extensible HTML (XHTML)
• Cascading Style Sheets (CSS)

13.What are all the features of Ajax?

Following are the features of Ajax and they are as follows:

• Live data binding
• Client-side template rendering
• Declarative instantiation of client components
• Observer pattern on JavaScript objects and arrays
• Invoking ADO.NET data services and data contexts
• DataView control

14.What is JSON in Ajax?

JSON is abbreviated as JavaScript Object Notation.
JSON is a safe and reliable data interchange format in JavaScript, which is easy to understand for both users and machines.

15.What are the components of the ASP.NET AJAX architecture?

There are two components of AJAX Architecture:

• AJAX client architecture
• AJAX server architecture

16.What are the extender controls?

The extender controls uses a block of JavaScript code to add new and enhanced capabilities to ASP.NET.

17.What is AJAX Control Extender Toolkit?

AJAX Control Toolkit is one of the extenders that are used to extend or add the functionalities of the ASP.NET controls. The extenders use a block of JavaScript code to add new and enhanced capabilities to the ASP.NET controls.
AJAX Control Extender Toolkit is a free download from site.

18.Where AJAX cannot be used?

Users cannot use AJAX if

• If Page need to show in a search engine
• If browser does not support JavaScript
• If user wants to create secure application

19.What are the pre-requisites to execute AJAX applications on a server?

AJAX is a built-in functionality of .NET Framework 4.0 and AJAX application can be executed by just installing MicrosoftVisual Studio 2010. To use extenders in your applications, you are required to install AJAX Control Toolkit and copy the AjaxControlToolkit.dll file to the Bin directory of your application.

20. What is AJAX Framework?

ASP.NET AJAX is a free framework to implement Ajax in asp.net web applications. It is used to quickly creating efficient and interactive Web applications that work across all browsers.