Talk to the server with Ajax

This lessons covers

• A brief overview of Ajax
• Loading preformatted HTML from the server
• Making GET and POST requests
• Exerting fine-grained control over requests
• Setting default Ajax properties
• Handling Ajax events

Ajax is one of the technologies that has heavily transformed the landscape of the web. The ability to make asynchronous requests back to the server without the need to reload entire pages has enabled a whole new set of user-interaction paradigms and made DOM-scripted applications possible.

A few years after Microsoft introduced Ajax, a handful of events launched it into the collective consciousness of the web development community. The non-Microsoft browsers implemented a standardized version of the technology as the XMLHttpRequest (XHR) object; Google began using XHR; and, in 2005, Jesse James Garrett of Adaptive Path coined the term Ajax (for Asynchronous JavaScript and XML).

As if they were only waiting for the technologies to be given a catchy name, the web development masses suddenly took note of Ajax in a big way, and it has become one of the primary means by which we can enable DOM-scripted applications.

In this lesson, we’ll take a brief tour of Ajax (if you’re already an Ajax guru, you might want to skip ahead to section 10.2), and then we’ll look at how jQuery makes using Ajax a snap. Let’s start off with a refresher on what Ajax technology is all about.