Ajax Interview Questions
1 .
What is Ajax ?
AJAX stands for Asynchronous JavaScript and XML.It is the use of the  XMLHttpRequest object to communicate with servers. The Ajax was publicly used on 18 February 2005 by Jesse James Garrett. Mainly we are creating interactive web applications. 
2 .
What are the advantages of Ajax ?
Following are the advantages of Ajax :

Quick Response
Bandwidth utilization -  It saves memory when the data is fetched from the same page.
User is not blocked until data is retrieved from the server.
More interactive
3 .
What are the disadvantages of AJAX ?
Following are the disadvantages of Ajax :

Dependent on JavaScript
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.
4 .
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)
5 .
What does XMLHttpRequest ?
sends data in the background
receives data
updates data without reloading the page
6 .
What are the properties of XMLHttpRequest ?
The important properties of XMLHttpRequest object are given below.

onReadyStateChange
readyState
responseText
responseXML
7 .
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
8 .
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
9 .
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.
10 .
What are all the browsers support AJAX ?
Internet Explorer 7.0 and above
Google Crome 36.0 and above
Opera 7.6 and above
Netscape 7.1 and above
Safari 1.2 and above