ASP.NET - ajax use in asp.net

Helo to all ... Can anybody tell me that  why we use ajax in asp.net.. what advantage will give ajax control  such

as we can see that calender control is in asp.net and also in ajax control.. so why we use ajax calender as both calender will give same functionality..

Thanks Dipa..You always help me

Hi,

 The advantage of using ajax controls is ,

 let us assume that we have an application without using ajax controlls and we some 5 controlls in it if when we click on a button it wil send the whole page to the server. evenif we want to validate one controlls also the whole page moves to the server side,

  coming to ajax if we are using ajax controlls in application , if we want to validate only one controll , than it can be done.
 i mean if want only one control to validate on the server side it is possible inspite of moving whole application to the server it validates only one control.

the difference between ajax calender and ordinary calender is if we ajax calender fits like a small controll , ie it can me minimised, where other asp control wont be minimised and it would be big in size.

Hi,

Asynchronous JavaScript + XML (AJAX) is a a bundle of common web technologies. Its having JavaScript, DHTML and a utility object called XMLHTTP. To prevent heavy server trip we use ajax, means you don't want to load whole page from server again and again then you can use ajax for this.  for eg you have a registration page and there is state and city combobox, you want the that if user select a particular state then only city belonging to that state should be fetch from database. For that there is not need to load and fetch whole registration page again and  again from server, you can use send request for two  combobox and then can download  the  data related to that combobox. Here is the situation we need to use ajax for that.