Excel does not have an OnSave event. However, it does have BeforeSave. BeforeSave occurs BEFORE the workbook is saved.
I quote from the VBA Help:
Syntax:
Private Sub Workbook_BeforeSave(ByVal SaveAsUi As Boolean, Cancel As Boolean)
SaveAsUi True if the Save As dialog box will be displayed.
Cancel False when the event occurs. If the event procedure sets this argument to True, the workbook isn't saved when the procedure is finished.
EXAMPLE:
This example prompts the user for a yes or no response before saving the workbook.
Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel as Boolean)
a = MsgBox("Do you really want to save the workbook?", vbYesNo)
If a = vbNo Then Cancel = True
End Sub
