Sub ValidDate()
Dim Ws As Worksheet
For Each Ws In ActiveWindow.SelectedSheets
With Ws.Range("A2:A10").Validation
.Delete
.Add Type:=xlValidateDate, AlertStyle:=xlValidAlertStop, Operator:=xlBetween, Formula1:="01/01/2013", Formula2:="01/01/2014"
.ErrorMessage = "La date doit être comprise entre le 01/01/2013 et le 31/12/2013"
End With
Next Ws
End Sub