Ajax Interview Questions
1 .
What is UpdatePanel control?
UpdatePanel allows rendering partial page. You can refresh important parts of the page instead of refreshing whole page.
2 .
What is UpdateProgress control?
UpdateProgress control  shows the progress for all partial-page updates on the page. You can use an UpdatePanel control for every UpdateProgress control.
3 .
What is ScriptManager control?
There is only one ScriptManager control in one page. It registers ajax library scripts for that page. It also creates proxies for asynchronous web service call.
4 .
What is ScriptManagerProxy control?
As mentioned above there is only one ScriptManager control in one page but the page can have multiple ScriptManagerProxy controls. If you have the ScriptManager in master page which will go across all pages, you cannot add another ScriptManager to underlying pages, instead ScriptManagerProxy control would be added to those underlying pages otherwise the page would show error.
5 .
What are some common ajax framework?
MooTools : It is one of the popular JavaScript toolkits which is primarily used for creating visual effects.

Google Web Toolkit (GWT) : It enables developers to create rich Ajax applications using Java.

Dojo Toolkit : It is most popular toolkit and used in large number of applications. It is a modular JavaScript toolkit which is distributed under an open-source license. Dojo toolkit includes many user interface effects, widget APIs, drag and drop AISs etc.

Yahoo User Interface(YUI) :  YUI library is an open source JavaScript framework and is used to make interactive applications.

Spry : This framework was developed by Adobe. It consists of animation and visual effects components, a data binding component, and a framework to crate widgets.
6 .
What is Rich Internet Application (RIA)?
It is a web application which has many characteristics of desktop application software. It has quick response time and many advanced functions. An RIA is browser dependent or require browser plugin or a virtual machine to deliver user application.
7 .
What is readyState in Ajax?
In AJAX, the readyState is a function to be called when the readyState property changes. It holds the status of the XMLHttpRequest.
8 .
What are the real-time AJAX web applications?
The different types of real-time applications include security authentications which can be applied for the AJAX web applications on the server side and client side as well. XML in AJAX is least used whereas the JSON is the most used data format for the exchange of information across different sources. AJAX also provides the feature of fetching resources using Fetch API of XMLHTTPRequest object.
9 .
How can concurrent AJAX requests be handled?
JavaScript closures are used to handle such synchronous requests. Firstly functions are built and then parameters (back function and URL) to corresponding functions are selected with the use of Closures and pass to AJAX URL Objects.
10 .
What is the difference between proxied and proxyless calls in AJAX?
Proxied : calls are made through stub objects which can be called from PHP classes on the JavaScript side in AJAX.
Proxyless : calls are made using utility JavaScript functions like HTML_AJAX.replace() and HTML_AJAX.append() in AJAX.