' Format a credit card numberFunction FormatCreditCard(ByVal text As String) As String    Dim i As Long        ' ignore empty strings    If Len(text) = 0 Then Exit Function        ' get rid of dashes, spaces and invalid chars    For i = Len(text) To 1 Step -1        If InStr("0123456789", Mid$(text, i, 1)) = 0 Then            text = Left$(text, i - 1) & Mid$(text, i + 1)        End If    Next    ' then, re-insert them in the correct position    FormatCreditCard = Format$(text, "!@@@@ @@@@ @@@@ @@@@")    End Function