Best Ajax Training Institute In Chennai Adyar With Placement

What is AJAX?

  • AJAX stands for Asynchronous JavaScript and XML. AJAX is a new technique for creating better, faster, and more interactive web applications with the help of XML, HTML, CSS, and Java Script.
  • Ajax uses XHTML for content, CSS for presentation, along with Document Object Model and JavaScript for dynamic content display.
  • Conventional web applications transmit information to and from the server using synchronous requests. It means you fill out a form, hit submit, and get directed to a new page with new information from the server.
  • With AJAX, when you hit submit, JavaScript will make a request to the server, interpret the results, and update the current screen. In the purest sense, the user would never know that anything was even transmitted to the server.
  • XML is commonly used as the format for receiving server data, although any format, including plain text, can be used.
  • AJAX is a web browser technology independent of web server software.
  • A user can continue to use the application while the client program requests information from the server in the background.
  • Intuitive and natural user interaction. Clicking is not required, mouse movement is a sufficient event trigger.
  • Data-driven as opposed to page-driven.

Rich Internet Application Technology

AJAX Training is the most viable Rich Internet Application (RIA) technology so far. It is getting tremendous industry momentum and several tool kit and frameworks are emerging. But at the same time, AJAX has browser incompatibility and it is supported by JavaScript, which is hard to maintain and debug.

AJAX is Based on Open Standards

AJAX is based on the following open standards:

  • Browser-based presentation using HTML and Cascading Style Sheets (CSS).
  • Data is stored in XML format and fetched from the server.
  • Behind-the-scenes data fetches using XMLHttpRequest objects in the browser.
  • JavaScript to make everything happen.

Understanding Synchronous vs Asynchronous

Before understanding AJAX, let’s understand classic web application model and ajax web application model first.

Synchronous (Classic Web-Application Model)

A synchronous request blocks the client until operation completes i.e. browser is not unresponsive. In such case, javascript engine of the browser is blocked.

As you can see in the above image, full page is refreshed at request time and user is blocked until request completes.

Let’s understand it another way.

Asynchronous (AJAX Web-Application Model)

An asynchronous request doesn’t block the client i.e. browser is responsive. At that time, user can perform another operations also. In such case, javascript engine of the browser is not blocked.

As you can see in the above image, full page is not refreshed at request time and user gets response from the ajax engine.

Let’s try to understand asynchronous communication by the image given below.

Ajax Events

Often, you’ll want to perform an operation whenever an Ajax request starts or stops, such as showing or hiding a loading indicator. Rather than defining this behavior inside every Ajax request, you can bind Ajax events to elements just like you’d bind other events.

// Setting up a loading indicator using Ajax Events
$( "#loading_indicator" )
.ajaxStart(function() {
$( this ).show();
})
.ajaxStop(function() {
$( this ).hide();
});