Libraries

WebHub

ZaphodsMap

TPack

NativeXml

ldiRegEx

htCreditCardValid Routine

Declaration

function htCreditCardValid(Value: string): Boolean;

Unit

ccValid

Description

True/False: credit card number may be valid

This routine determines whether a card number COULD be valid. This is a good preliminary check, to prevent extreme fraudulant use of a web ordering system. Any card number which fails this test is not worth using for any real transaction.

The types of cards which can be identified by this technique are defined by ThtCCardType.

Typically the next step is to process the card against an ecommerce interface which contacts a bank (merchant account). That step is outside the scope of ccValid.pas.

Example

uses
  ccValid;

procedure TForm1.BitBtn1Click(Sender: TObject);
var
  a1: string;

  function Ok(Value: Boolean): string;
  begin
    if Value then
      Result := 'OK'
    else
      Result := 'Invalid';
  end;

begin
  a1 := Edit1.Text;   // cc number to check is in this edit box
  MessageDlg(a1 +
      ' -> ' + htCreditCardName(htCreditCardType(a1)) +
      ' -> ' + Ok(htCreditCardValid(a1)),
      mtInformation, [mbOk], 0);
end;