The term Ajax was first coined in 2005, although the techniques for the asynchronous loading of content date back to 1996. This was done by Internet explorers IFRAME element. Since then, more elegant replacements for these techniques have been introduced. The term Ajax now represents a broad group of web technologies. These technologies can be used for implementing a web application that can communicate with the server, without interfering with the current state of the page. Jesse James Garret explained in an article that coined the term Ajax, that it referred to these techniques: XHTML, CSS, XML, XSLT, Javascript and more.
The advantages of using Ajax include : lowered bandwidth usage and load time by requesting only content that needs to be updated is updated, instead of updating on every request. The Web browsers UI is more interactive and responds quicker to inputs. Also, Ajax can reduce connections to the server, since server scripts etc only need to be requested once.
Degradable Ajax is used for users of your site that don’t have Javascript enabled. By not making your website degradable, you exclude users from an experience on your site by no fall back for when things go wrong client side. Making your website degradable Ajax should rely on two things: Functionality – Does your site work without Javascript? And cost – Is it worth making the site degradable Ajax compatible?
J-query is much easier to use than raw Javascript. It is small, lightweight and facilitates a common dialog among modern browsers. J-query helps Ajax by through its ability to use functions that don’t need an object. A Lot of Ajax functions fall into this group.
