AJAX… how does it work?

Although some people had already written something about AJAX, I try to explain the advantages of how AJAX will work and what the differences to old-fashioned sites are.

Websites that does not use AJAX-technology shows the content that the server has transferred to the client. By clicking on a hyperlink, e.g. for reading the next blog post or to show details of a product, the client will request the target site. The server will send this requested site with all connected data (e.g. pictures, videos or sounds) and the client starts to display the site on the browser. In case that some data is delayed the representation of the site will be delayed as well. The user might not be able to use that website and might loose interest in the website.


Using AJAX means that the server first sends the website and afterwards will only send the requested data. The clicking on a link means starting a JavaScript-Procedure that will request only needed data. The server will send only this data to the client where it will be integrated to the website (by changing some parts of the websites).


The advantages of this technique are that the load on a server and the sent data will be reduced. On the client side, applications seem more like desktop application than web applications.



Sources:
Ajax Programming for the Absolute Beginnerby Jerry Lee Ford, Jr.,
http://en.wikipedia.org/wiki/Ajax_(programming)