what is Ajax?how to use and it working ? ajax work as?

Ajax is a set of programming :

techniques or a particular approach to web programming. These

programming techniques involve being able to seamlessly update a web page or a section of a web
application with input from the server, but without the need for an immediate page refresh. This doesn’t
mean that the browser doesn’t make a connection to the web server. Indeed, the original article paints a
slightly incomplete picture in that it fails to mention that server-side technologies are often still needed.
It is very likely that your page, or data from which the page is drawn, must still be updated at some
point by a rendezvous with the server. What differs in the Ajax model is that the position at which the
page is updated is moved. We’ll look at the two models in more detail shortly.

In previous post I explained post relating to XML some of those are read xml file and bind data to Asp.net grid view, xml data to dropdownlist or gridview in asp.net and how to insert and read data from xml in asp.net. In situation I got requirement like read data from xml file and display it on webpage. My XML File Name as “SampleDemofor.xml” and that would contains data like this