hi,i have a gridview that i put its pic here.

i want as soon as Keyup Event Occured In GridView Textboxes Automatically sum of columns A and B be calculate and put in column C.Can Anybody Write its code for me using java script or jqurery?
Tip:I want GridView Always Have An empty Row In Its Bottom But Not In Footer Template But Also In Last Rows Of Its Item Template,ie,as soon as user filled last row of gridview,automatically add a new row to grid view.
thanks in advance

i want as soon as Keyup Event Occured In GridView Textboxes Automatically sum of columns A and B be calculate and put in column C.Can Anybody Write its code for me using java script or jqurery?
Tip:I want GridView Always Have An empty Row In Its Bottom But Not In Footer Template But Also In Last Rows Of Its Item Template,ie,as soon as user filled last row of gridview,automatically add a new row to grid view.
thanks in advance