In the exit event try following FormCalc code...if (HasValue($)) then $.rawValue = Replace($.rawValue, ".", "") if (Left($.rawValue, 1) <> "I" and Len($.rawValue) < 6) then xfa.host.messageBox("At leaset 5 degits followed by I is required.") elseif (Left($.rawValue, 1) <> "I") then xfa.host.messag...