Before going into details about AJAX, it is very essential to mention what AJAX stands for from a layman’s point of view. It is a collection of web technologies put together that enables dynamic client-server interactions to take place in web applications without the need for refreshing or reloading pages. It is the abbreviation for Asynchronous JavaScript and XML.

AJAX uses HTML or XHTML and CSS to build an interface and visually style information. The various elements in CSS and XHTML can be dynamically modified to show new styling or information. Document Object Model is the tool used to bring about these changes. JavaScript is also used in AJAX to modify the interface elements and set up a communication with a web server through XMLHttpRequest. As a result, the data in XML format can be transmitted between the client and the web server without the need for page refreshes or reloads. The typical client-server interaction is not there while using AJAX. But it still allows a higher level of interactivity and processing. A standard client-server interaction has the following steps:

• A user interface is presented.
• User information is gathered through forms or links.
• The user submits information by submitting forms or activating links.
• The server processes the submitted information.
• A new web page is presented to the user.

By using AJAX, all these steps can be handled in one interface. AJAX can be used for various applications ranging from mapping applications, live shopping cart applications, e-mail applications to real-time searches, chats and real-time form validation and processing. It has brought a revolution in the web technology by introducing a term “Web 2.0” due to its type of web applications and interactions.

AJAX allows the use of server-side processing without requiring the standard submit data — retrieve web page methodology. Using XMLHttpRequest, data is transmitted to the backend of your web application and JavaScript is used to manipulate the application interface and display dynamic information. This enables more streamlined applications that require less processing and data transmission because the whole web pages do not need to be generated for each change that occurs. Instead, one web application reflects all of the changes that occur. JavaScript can also be used to allow higher levels of interactivity that is not possible through HTML, like keyboard shortcuts, click and drag, etc.

In between all these easy accessibility features, there lie some pitfalls of AJAX. It is not supported by all browsers, because its applications will not run in web browsers and devices that that do not support JavaScript. AJAX also requires XMLHttpRequest to be supported by browsers which many browsers do not. It tends to manipulate and update elements quickly, i.e. on the fly. So the users may not be able to know when their information is being processed and saved. AJAX can also submit information to the server without user interaction and contains certain methods which carry out this task that are not known to the user. It also dose not display any visual cues that a particular web page has been reloaded or refreshed. The possible solution to these problems is to either provide an alternative to AJAX or to allow your AJAX application to run even if JavaScript or XMLHttpRequest are not supported. The both solutions are very difficult to achieve. So the web developers may choose to require the users to use a browser that supports AJAX.

Tags: User-friendliness of AJAX