AJAX Controls

AJAX : Asynchronous JavaScript and XML.
 for creating fast and dynamic web pages.
by this  it is possible to update parts of a web page, without reloading the whole page...
partially refreshing.
to implement AJAX we must use "SCRIPTMANAGER" control in the webpage.

UPDATEPANEL control:update the part of webpage.all the controls, whom u want to be refresh must be in the update panel control.

TIMER control: use for timing.
property "time interval"in which u enter the time after which the web page will be upadate.

simple program for the clock...

take scriptmanager ,updatepanel, timer and  label .....
place label,timer in the update panel..

change the "time interval" property of timer to "1000"
in the page load event write the code

                      Label1.Text = DateTime.Now.ToString();

datetime.now provides the current time in label and update panel refersh the label control  after 1 sec.....