Ajax Introduction

• AJAX stands for Asynchronous JavaScript and XML. AJAX is a new technique for creating better, faster, and more interactive web applications with the help of XML, HTML, CSS and Java Script.
• Ajax uses XHTML for content and CSS for presentation, as well as the Document Object Model and JavaScript for dynamic content display.
• Conventional web application trasmit information to and from the sever using synchronous requests. This means you fill out a form, hit submit, and get directed to a new page with new information from the server.
• With AJAX when submit is pressed, JavaScript will make a request to the server, interpret the results and update the current screen. In the purest sense, the user would never know that anything was even transmitted to the server.
• XML is commonly used as the format for receiving server data, although any format, including plain text, can be used.
• AJAX is a web browser technology independent of web server software.
• A user can continue to use the application while the client program requests information from the server in the background
• Intuitive and natural user interaction. No clicking required only Mouse movement is a sufficient event trigger.
• Data-driven as opposed to page-driven

AJAX is based on the following open standards:

• Browser-based presentation using HTML and Cascading Style Sheets (CSS)
• Data stored in XML format and fetched from the server
• Behind-the-scenes data fetches using XMLHttpRequest objects in the browser
• JavaScript to make everything happen