2 of 5

Write now Article Tools

What is AJAX? Well, the textbook definition, Asynchronous JavaScript and XML, is not of much help to the average reader and may only get us so far as to realize we are not discussing a cleaning product. While the name implies the use of XML, AJAX is the appropriate term for any web sites that perform HTTP Requests in order to dynamically update the content of the screen without refreshing your web browser page. To clarify this a little bit, let's compare the AJAX request to ordering a meal in a restaurant. When you sit down to a restaurant, you request a specific item from a waitress. Whether you order a steak cooked medium-rare or a hot fudge sundae with an extra cherry, once the waitress leaves your table, your experience doesn't really change. You simply sit and wait for her to bring back your order, and if, for some reason your request cannot be completed as ordered, she brings back information as to why that is the case.

Allowing AJAX to work for you is much the same principle. When visiting a traditional web site, the user is required to move from one page to the next and retrieve somewhat static information on each: even if that information is generated dynamically, once it reaches the screen, to the user, it just sits there. Enter AJAX and HTTP Requests. Using JavaScript, a web page can place an order for information or data as often as needed, and the page will send the request out. A request, when sent, targets a specific data source: usually another file on the server. Whatever data the HTTP Request collects is then returned to the requesting page to be handled in whatever fashion the page's creator intended. The responding text is typically used to update a specific portion of the page the user is viewing. This allows for live updating of information on a page without ever forcing the user to have a full page refresh.

One of the beauties of using AJAX to update your pages is not simply in the retrieval of the data itself, but also in the handling of the data upon its return. Creative web developers often send out AJAX requests for a portion of their page every few seconds for a live feed, and they may animate the update to make the page very smooth and attractive to the user. Another great use of this technology is to collect information in a form and send an AJAX request when the form is submitted to validate and save the user's information without forcing them to wait for a full page reload.

Just as you can sit down at one seat comfortably and allow employees of a restaurant to prepare and serve your order to you, with appropriate implementation of AJAX, you can browse to a single page and have unlimited information actively at your disposal. This technology is blurring the line between web and desktop applications more and more.

Learn more about this author, Obsidian.
Click here to send this author comments or questions.

Add your voice

Know something about Ajax web technology explained?
We want to hear your view. Write now!