function ValidateCard() 
{
	var error = 0;
	var error_message = "";
	var temp = "";
	
	if(document.card.cardtype.selectedIndex == 0)
	{	
		
		error = 1;
		error_message = "You must select a card type.";
	}
	
	if(document.card.cardtype.value == "visa")
	{	
		temp = isVisa(document.card.ccard.value);		
		if(temp == true)
		{}
		else
		{
			error = 1;
			error_message = "The card number you have entered is not a valid Visa number.";
		}
	}

	if(document.card.cardtype.value == "mastercard")
	{	
		temp = isMasterCard(document.card.ccard.value);		
		if(temp == true)
		{}
		else
		{
			error = 1;
			error_message = "The card number you have entered is not a valid MasterCard number.";
		}
	}
	
	if(document.card.cardtype.value == "amex")
	{	
		temp = isAmericanExpress(document.card.ccard.value);		
		if(temp == true)
		{}
		else
		{
			error = 1;
			error_message = "The card number you have entered is not a valid American Express number.";
		}
	}
	
	if(document.card.cardtype.value == "dinersclub")
	{	
		temp = isDinersClub(document.card.ccard.value);		
		if(temp == true)
		{}
		else
		{
			error = 1;
			error_message = "The card number you have entered is not a valid Diners Card number.";
		}
	}
	
	if(document.card.cardtype.value == "carte")
	{	
		temp = isCarteBlanche(document.card.ccard.value);		
		if(temp == true)
		{}
		else
		{
			error = 1;
			error_message = "The card number you have entered is not a valid Carte Blanche number.";
		}
	}
	
	if(document.card.cardtype.value == "discover")
	{	
		temp = isDiscover(document.card.ccard.value);		
		if(temp == true)
		{}
		else
		{
			error = 1;
			error_message = "The card number you have entered is not a valid Discover number.";
		}
	}
	
	if(document.card.cardtype.value == "enroute")
	{	
		temp = isEnRoute(document.card.ccard.value);		
		if(temp == true)
		{}
		else
		{
			error = 1;
			error_message = "The card number you have entered is not a valid EnRoute number.";
		}
	}
	
	if(document.card.cardtype.value == "jcb")
	{	
		temp = isJCB(document.card.ccard.value);		
		if(temp == true)
		{}
		else
		{
			error = 1;
			error_message = "The card number you have entered is not a valid JCB number.";
		}
	}
				
if(error ==1){
		alert(error_message);
	}
	else {
		document.card.submit();
	}	
}	
/*  ================================================================
    Credit card verification functions
    Originally included as Starter Application 1.0.0 in LivePayment.
    20 Feb 1997 modified by egk:
           changed naming convention to initial lowercase
                  (isMasterCard instead of IsMasterCard, etc.)
           changed isCC to isCreditCard
           retained functions named with older conventions from
                  LivePayment as stub functions for backward 
                  compatibility only
           added "AMERICANEXPRESS" as equivalent of "AMEX" 
                  for naming consistency 
    ================================================================ */


/*  ================================================================
    FUNCTION:  isCreditCard(st)
 
    INPUT:     st - a string representing a credit card number

    RETURNS:  true, if the credit card number passes the Luhn Mod-10
		    test.
	      false, otherwise
    ================================================================ */

function isCreditCard(st) {
  // Encoding only works on cards with less than 19 digits
  if (st.length > 19)
    return (false);

  sum = 0; mul = 1; l = st.length;
  for (i = 0; i < l; i++) {
    digit = st.substring(l-i-1,l-i);
    tproduct = parseInt(digit ,10)*mul;
    if (tproduct >= 10)
      sum += (tproduct % 10) + 1;
    else
      sum += tproduct;
    if (mul == 1)
      mul++;
    else
      mul--;
  }
// Uncomment the following line to help create credit card numbers
// 1. Create a dummy number with a 0 as the last digit
// 2. Examine the sum written out
// 3. Replace the last digit with the difference between the sum and
//    the next multiple of 10.

//  document.writeln("<BR>Sum      = ",sum,"<BR>");
//  alert("Sum      = " + sum);

  if ((sum % 10) == 0)
    return (true);
  else
    return (false);

} // END FUNCTION isCreditCard()



/*  ================================================================
    FUNCTION:  isVisa()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is a valid VISA number.
		    
	      false, otherwise

    Sample number: 4111 1111 1111 1111 (16 digits)
    ================================================================ */

function isVisa(cc)
{
  if (((cc.length == 16) || (cc.length == 13)) &&
      (cc.substring(0,1) == 4))
    return isCreditCard(cc);
  return false;
}  // END FUNCTION isVisa()




/*  ================================================================
    FUNCTION:  isMasterCard()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is a valid MasterCard
		    number.
		    
	      false, otherwise

    Sample number: 5500 0000 0000 0004 (16 digits)
    ================================================================ */

function isMasterCard(cc)
{
  firstdig = cc.substring(0,1);
  seconddig = cc.substring(1,2);
  if ((cc.length == 16) && (firstdig == 5) &&
      ((seconddig >= 1) && (seconddig <= 5)))
    return isCreditCard(cc);
  return false;

} // END FUNCTION isMasterCard()





/*  ================================================================
    FUNCTION:  isAmericanExpress()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is a valid American
		    Express number.
		    
	      false, otherwise

    Sample number: 340000000000009 (15 digits)
    ================================================================ */

function isAmericanExpress(cc)
{
  firstdig = cc.substring(0,1);
  seconddig = cc.substring(1,2);
  if ((cc.length == 15) && (firstdig == 3) &&
      ((seconddig == 4) || (seconddig == 7)))
    return isCreditCard(cc);
  return false;

} // END FUNCTION isAmericanExpress()




/*  ================================================================
    FUNCTION:  isDinersClub()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is a valid Diner's
		    Club number.
		    
	      false, otherwise

    Sample number: 30000000000004 (14 digits)
    ================================================================ */

function isDinersClub(cc)
{
  firstdig = cc.substring(0,1);
  seconddig = cc.substring(1,2);
  if ((cc.length == 14) && (firstdig == 3) &&
      ((seconddig == 0) || (seconddig == 6) || (seconddig == 8)))
    return isCreditCard(cc);
  return false;
}



/*  ================================================================
    FUNCTION:  isCarteBlanche()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is a valid Carte
		    Blanche number.
		    
	      false, otherwise
    ================================================================ */

function isCarteBlanche(cc)
{
  return isDinersClub(cc);
}




/*  ================================================================
    FUNCTION:  isDiscover()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is a valid Discover
		    card number.
		    
	      false, otherwise

    Sample number: 6011000000000004 (16 digits)
    ================================================================ */

function isDiscover(cc)
{
  first4digs = cc.substring(0,4);
  if ((cc.length == 16) && (first4digs == "6011"))
    return isCreditCard(cc);
  return false;

} // END FUNCTION isDiscover()





/*  ================================================================
    FUNCTION:  isEnRoute()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is a valid enRoute
		    card number.
		    
	      false, otherwise

    Sample number: 201400000000009 (15 digits)
    ================================================================ */

function isEnRoute(cc)
{
  first4digs = cc.substring(0,4);
  if ((cc.length == 15) &&
      ((first4digs == "2014") ||
       (first4digs == "2149")))
    return isCreditCard(cc);
  return false;
}



/*  ================================================================
    FUNCTION:  isJCB()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is a valid JCB
		    card number.
		    
	      false, otherwise
    ================================================================ */

function isJCB(cc)
{
  first4digs = cc.substring(0,4);
  if ((cc.length == 16) &&
      ((first4digs == "3088") ||
       (first4digs == "3096") ||
       (first4digs == "3112") ||
       (first4digs == "3158") ||
       (first4digs == "3337") ||
       (first4digs == "3528")))
    return isCreditCard(cc);
  return false;

} // END FUNCTION isJCB()



/*  ================================================================
    FUNCTION:  isAnyCard()
 
    INPUT:     cc - a string representing a credit card number

    RETURNS:  true, if the credit card number is any valid credit
		    card number for any of the accepted card types.
		    
	      false, otherwise
    ================================================================ */

function isAnyCard(cc)
{
  if (!isCreditCard(cc))
    return false;
  if (!isMasterCard(cc) && !isVisa(cc) && !isAmericanExpress(cc) && !isDinersClub(cc) &&
      !isDiscover(cc) && !isEnRoute(cc) && !isJCB(cc)) {
    return false;
  }
  return true;

} // END FUNCTION isAnyCard()



/*  ================================================================
    FUNCTION:  isCardMatch()
 
    INPUT:    cardType - a string representing the credit card type
	      cardNumber - a string representing a credit card number

    RETURNS:  true, if the credit card number is valid for the particular
	      credit card type given in "cardType".
		    
	      false, otherwise
    ================================================================ */

function isCardMatch (cardType, cardNumber)
{

	cardType = cardType.toUpperCase();
	var doesMatch = true;

	if ((cardType == "VISA") && (!isVisa(cardNumber)))
		doesMatch = false;
	if ((cardType == "MASTERCARD") && (!isMasterCard(cardNumber)))
		doesMatch = false;
	if ( ( (cardType == "AMERICANEXPRESS") || (cardType == "AMEX") )
                && (!isAmericanExpress(cardNumber))) doesMatch = false;
	if ((cardType == "DISCOVER") && (!isDiscover(cardNumber)))
		doesMatch = false;
	if ((cardType == "JCB") && (!isJCB(cardNumber)))
		doesMatch = false;
	if ((cardType == "DINERS") && (!isDinersClub(cardNumber)))
		doesMatch = false;
	if ((cardType == "CARTEBLANCHE") && (!isCarteBlanche(cardNumber)))
		doesMatch = false;
	if ((cardType == "ENROUTE") && (!isEnRoute(cardNumber)))
		doesMatch = false;
	return doesMatch;

}  // END FUNCTION CardMatch()




/*  ================================================================
    The below stub functions are retained for backward compatibility
    with the original LivePayment code so that it should be possible
    in principle to swap in this new module as a replacement for the  
    older module without breaking existing code.  (There are no
    guarantees, of course, but it should work.)

    When writing new code, do not use these stub functions; use the
    functions defined above.
    ================================================================ */

function IsCC (st) {
    return isCreditCard(st);
}

function IsVisa (cc)  {
  return isVisa(cc);
}

function IsVISA (cc)  {
  return isVisa(cc);
}

function IsMasterCard (cc)  {
  return isMasterCard(cc);
}

function IsMastercard (cc)  {
  return isMasterCard(cc);
}

function IsMC (cc)  {
  return isMasterCard(cc);
}

function IsAmericanExpress (cc)  {
  return isAmericanExpress(cc);
}

function IsAmEx (cc)  {
  return isAmericanExpress(cc);
}

function IsDinersClub (cc)  {
  return isDinersClub(cc);
}

function IsDC (cc)  {
  return isDinersClub(cc);
}

function IsDiners (cc)  {
  return isDinersClub(cc);
}

function IsCarteBlanche (cc)  {
  return isCarteBlanche(cc);
}

function IsCB (cc)  {
  return isCarteBlanche(cc);
}

function IsDiscover (cc)  {
  return isDiscover(cc);
}

function IsEnRoute (cc)  {
  return isEnRoute(cc);
}

function IsenRoute (cc)  {
  return isEnRoute(cc);
}

function IsJCB (cc)  {
  return isJCB(cc);
}

function IsAnyCard(cc)  {
  return isAnyCard(cc);
}

function IsCardMatch (cardType, cardNumber)  {
  return isCardMatch (cardType, cardNumber);
}