Recently one of friends asked me how to learn AJAX? Is it all about JavaScript and XML and sending asynchronous data? Though the term AJAX stand for Asynchronous JavaScript and XML. That means the term talks about how to asynchronously retrieve data from server using JavaScript and XML, but actually, AJAX goes much beyond that. It is more about providing a rich experience to users. A rich user experience can be simply stated as a ‘desktop application like feel’; now, desktop applications can have the luxury of heavy weight rich User Interfaces and with AJAX the same is possible for web applications, which so far could afford only a basic UI. With AJAX, the need for reloading the UI again and again with every request is gone; we will understand this more in rest of the document.

AJAX in itself is not a language or a framework. It is a technique. It basically uses XMLHTTPRequest Object to fetch the data from server without reloading the page. Additional AJAX supporters are CSS, DOM, DHTML and XSL.

Another keyword you will observe is Asynchronous. Asynchronous communication in general terms means that a browser does not wait for a reply from server once a request is sent. Hence, it does not stop user from interacting with the page while the information is being fetched from server. The data is retrieved as a back ground process and the web page does not get refreshed, the data is displayed dynamically at runtime giving the web application a feel of desktop application and hence improves user experience.

You might question if AJAX is more than just JavaScript and XML, why is it called AJAX? This is what Jesse James Garrett, the man who coined the term AJAX has to say about it “I needed something shorter than ‘Asynchronous JavaScript + CSS + DOM + XMLHttpRequest’ to use when discussing this approach with clients.” hence the term AJAX