In AJAX we use Asynchronous communication request/response model.decoupling user interaction from server interaction. As a result, the user can continue to use the application while the client program requests information from the server in the background. When new information arrives, only the related user interface portion is updated.And this is a big important point in the benfits

Exactly the process is like this only.
Due to this process user get information from the server...
Without undergoing of complete reloading of a page...