You mean you want to submit data or save your data to your data source when you click on sheet tab to navigate to other worksheet page. Well, you may utilize SheetTableClick event handler and write your SubmitCommand or SaveCommand GridWeb's events code there. And also please make sure that SessionMode (property) of the GridWeb control should be set to Session.
If you want to have some other means like you have a Asp.Net command button, you may write your code there in its Click event and write a line of code in the PageLoad event handler
Button1.Attributes["onclick"] = "GridWeb1.updateData(); return GridWeb1.validateAll();";