AJAX = Asynchronous JavaScript and XML
AJAX is not a new programming language, but a new technique for creating better, faster, and more interactive web applications. With AJAX, a JavaScript can communicate directly with the server, with the XMLHttpRequest object. With this object, a JavaScript can trade data with a web server, without reloading the page.
AJAX uses asynchronous data transfer (HTTP requests) between the browser and the web server, allowing web pages to request small bits of information from the server instead of whole pages.
The AJAX technique makes Internet applications smaller, faster and more user-friendly.
AJAX is based on Internet standards
AJAX is based on the following web standards:
JavaScript
XML
HTML
CSS
AJAX applications are browser- and platform-independent.
AJAX is about better Internet-applications
Internet-applications have many benefits over desktop applications; they can reach a larger audience, they are easier to install and support, and easier to develop.
However, Internet-applications are not always as "rich" and user-friendly as traditional desktop applications.
With AJAX, Internet applications can be made richer and more user-friendly.