Ajax Interview Question
Ajax Interview Questions
Ajax Interview Question for Freshers
What is Ajax ?
AJAX is not programming or script language, no new invention and no separate Web service. It is a group of related technologies to display data asynchronously.
Full form of ajax ?
Ajax stands for Asynchronous JavaScript and XML. The word "asynchronous" means that the user need not wait until the server replies.
Why use Ajax ?
AJAX allows you to send only important information to the server not the entire page. So only valuable data from the client side is routed to the server side. It makes your application interactive and faster.
What is Google Suggest ?
AJAX was made popular in 2005 by Google, with Google Suggest. Google Suggest is using AJAX to create a very dynamic web interface: When you start typing in Google's search box, a JavaScript sends the letters off to a server and the server returns a list of suggestions without reload that page.
Which technologies are used in ajax ?
- Html
- CSS
- DOM
- JavaScript
- XML or JSON
What are the main Advantage of Ajax ?
The main Advantage of Ajax are given below;
- No pushing on a submit button and reloading of a complete Website are needed.
- No need to reload the whole page only some part of page is reloaded which is required to reload.
- Increase the Performance of web page.
- Independent of server technology.
- Apart from obtaining the XMLHTTP object, all processing is same for all browser types, because JavaScript is used.
- Permits the development of faster and more interactive web applications.
- No require to completely reload page you are really using less server bandwidth.
Which web applications are running on ajax ?
There are too many web applications running on the web that are using ajax technology like gmail, facebook,twitter, google map, youtube etc.
Why use XMLHttpRequest object in ajax ?
An Object of XMLHttpRequest is used for asynchronous communication between client and server.
What is Callback Function ?
A callback function is a function passed as a parameter to another function.
What are dis-Advantage of ajax ?
Ajax have many advantage but every technology have some dis-Advantage, Some Dis-Advantage of Ajax are given below
- The back button problem. People think that when they press back button, they will return to the last change they made, but in AJAX this doesn't hold.
- Possible network latency problems. People should be given feedback about the processing.
- It Doesn't run on all browsers.
- Search Engine like Google cannot index AJAX pages.
- Security is less in AJAX application. Anyone can view the source code written for AJAX.
Difference between AJAX and Javascript
| Ajax | JavaScript |
|---|---|
| AJAX sends request to the server and does not wait for the response. It performs other operations on the page during that time | JavaScript make a request to the server and waits for response |
| AJAX does not require the page to refresh for downloading the whole page | JavaScript manages and controls a Web page after being downloaded |
| AJAX minimizes the overload on the server since the script needs to request once | JavaScript posts a request that updates the script every time |
Where AJAX cannot be used ?
- Where page need to show on search engine, because search engine can not index ajax related web page.
- If web browser does not support javascript.
- In case of secure application.
How can we cancel the XMLHttpRequest in AJAX ?
Abort() method can be called to cancel the XMLHttpRequest in Ajax.
What is the name of object used for AJAX request ?
XmlHttpRequest object is used for Ajax requests.
What are the Most Popular AJAX framework ?
- Angular JS
- Backbone.js
- Prototype
- Ext JS
- jQuery and jQuery UI
What are the Benefits of AJAX ?
- Cross-browser & cross-platform compatibility
- Better & richer user experience
- Web programming flexibility
- Reduced consumption of server resources
What does AJAX do ?
Ajax can exchanges the data between client and server and the data is in the form of text, XML, or JSON.
How to debug AJAX Application ?
Debugging of Ajax application is differ browser to browser, If you want to debug in Google Chrome, then use Chrome Developer Tool. On Mozilla Firefox, with the help of Firebug, debugging can be done easily.
What are the disadvantages of Ajax
Dependent on JavaScript, not secure, code debugging is difficult.
Which Application currently running in the market ?
Some Real Life Example of Ajax Application which currently running in market are given below;
- Google map
- Gmail
- Yahoo
What are the security issues with Ajax ?
Ajax source code is readable.
What does XMLHttpRequest
Send or received data to server in the background, and update date without reloading whole page.
What are the important methods of XMLHttpRequest
- open()
- send()
- setRequestHeader()
Is Ajax support JSON
Yes
Explain Functionalities Provided by XMLHttpRequest
Update a web page without reloading the entire page. Request receive and send data in the background after the page has loaded.
What is synchronous request in AJAX ?
In synchronous request, the usual working of a page and user interaction is blocked until a response is received from the server.
What is asynchronous request in AJAX ?
In an asynchronous request, the page continues to work normally without blocking the user. It is the most preferred way of sending a request.