Asynchronous JavaScript and XML

Ajax using jQuery

Http method & AJAX

What is AJAX? and Why it is important?

In the previous topics of “Front-End Web Development” course, you have learnt how to develop web pages using jQuery. As a web developer, to create interactive web applications using jQuery you must be familiar with AJAX. During this lesson you will get a basic understanding of what is AJAX and why it is important.

To better understand AJAX, let's first learn the meaning of asynchronous.

What is Asynchronous?

The meaning of asynchronous is not simultaneous or not occurring at the same time, and relating to computer applications, asynchronous means that an event can occur independently without waiting for another event.

In programming, synchronous operations are carried out one task at a time. When one task is completed, the next step begins. In the Figure 1, it displays how synchronous and asynchronous approaches works.

Figure 1: Synchronous VS Asynchronous

Synchronous approach

• Carries one task at a time and waits until previous task is completed.
• Synchronous calls are suitable when it is necessary to execute tasks in a sequence and when it does not require much time for execution.

Asynchronous approach

• Tasks occur independently without waiting for another task.