Despite the fact that AJAX is at the centre of the current Web 2.0 movement it is still a greatly misunderstood technology. So what is it?
Traditional web applications require the entire page to refresh whenever the user interacts with the system this is because the entire webpage is rebuilt following the transfer of data between the browser and the server (there is a synchronicity between a user’s action and data transfer between the web browser and the web server – the user clicks on something, data is transfered and the page is rebuilt).
Rebuilding the page in this way introduces a delay and interrupts the user from achieving their goal, which is obviously a bad thing; at least for web applications if not for sites such as this blog or a news site.
I would now like to draw a distinction between Ajax and DHTML (Dynamic HTML) which is often used to make rollover or drop-down buttons on a web page and is often confused with Ajax.
In other words if there is no data transfer between the server and the browser – it’s not Ajax.