Hi

You can do this by using the Ajax Timer control. Do the following :

1. Put an Ajax ScriptManager control on the page
2. Wrap all your controls inside an UpdatePanel control
3. Set the enabled property of the Timer control to True and set the Interval property appropriatly. It is in milliseconds i.e 1000  = 1 second.
4. Map the Tick event of the Timer and in this event write your code for saving the values from the form to database.

Refer:

http://www.codeproject.com/KB/aspnet/AutoSaveFormData.aspx

http://forums.asp.net/p/1510020/3594968.aspx

 http://forums.asp.net/p/1531233/3707371.aspx