JavaScript® Programmer's Reference

Chapter 19. Ajax

One could argue that few technological advances have done more to advance the web as a platform for business applications than Ajax or (Asynchronous JavaScript and XML). The term appeared in 2005 in an article by Jesse James Garrett called Ajax: A New Approach to Web Applications describing an assortment of web technologies that developers had been using to improve the overall experience of rich user interfaces. These technologies included:

• Cascading Style Sheets and XHTML for layout.

• The DOM for manipulation of the layout and interactivity.

• XML and XSLT for the exchange and manipulation of data.

• A JavaScript mechanism known as XMLHttpRequest for asynchronous communication with the server after the page has loaded.

• JavaScript to tie everything together.

Although the author of the article played no part in inventing any of these things, or even in using them together, he did add something of value to the mix: marketing. Staying on top of web technologies is a full-time job, and the term Ajax made it easy to classify and communicate a more advanced breed of rich-client development methodologies. The cornerstone of Ajax, XMLHttpRequest, was indeed a new idea to many developers, and the sudden media interest in JavaScript inspired an army of developers to learn about this new style of development and also contribute to the community while they were doing so.

Since then, Ajax has become synonymous with XMLHttpRequest, which is what allows you to contact the server on demand ...