How does AJAX work?

Question

What is the essence of AJAX? For example, I want to have a link on my page such that when a user clicks this link, some information is sent to my server without the reloadin

Answer 1

AJAX typically involves sending HTTP requests from client to server and processing the server's response, without reloading the entire page. (Asynchronously).

Javascript generally does the submission and receives the data response from the server (traditionally XML, often other less verbose formats like JSON)

The Javascript then may update the page DOM dynamically to update the user's view.

Thus 'Asychronous Javascript And XML'.

There are other options to update the user's view without reloading the page, things like Flash and Applets, but these don't sound like good solutions for your case. Sounds like Javascript is the way to go. There's loads of good library support around, like jQuery as is used on this site, so you don't need to actually write much Javascript yourself.