Ajax
Ajax is only a name given to a set of tools that were previously existing.
The main part is XMLHttpRequest, a class usable in JavaScript , that was implemented into Internet Explorer since the 4.0 version.
The same concept was named XMLHTTP some times, before the Ajax name becomes commonly used.
The use of XMLHttpRequest in 2005 by Google, in Gmail and GoogleMaps has contributed to the success of this format. But this is the name Ajax itself that made the technology so popular
Ajax is a set of technologies, supported by a web browser, including these elements:
- HTML and CSS for presenting.
- JavaScript (ECMAScript) for local processing, and DOM (Document Object Model) to access data inside the page or to access elements of XML file read on the server (with the getElementByTagName method for example)...
- The XMLHttpRequest class read or send data on the server asynchronously.
How does it work?
Instead of a user request being made of the server via, for example, a normal HTTP POST or GET request, such as would be made by submitting a form or clicking a hyperlink, an Ajax script makes a request of a server by using the Javascript XMLHTTPRequest object.
Although this object may be unfamiliar to many, in fact it behaves like a fairly ordinary javascript object. As you may well know, when using a javascript image object we may dynamically change the URL of the image source without using a page refresh. XMLHTTPRequest retrieves information from the server in a similarly invisible manner.
Tutorials
