// Credit Card Format Validator

// Version 1.0 completed April 28, 2002

// Programmer:  William Bontrager

// Website: http://willmaster.com



// Customization:

//

// There are 4 customization steps:

//



// Step 1:

// Between the quotes, type what the alert box message shall say when

// the credit card is unknown and the number did not pass?

// To force a line break, use "\n" (without the quotes).

// For no message, type "" (nothing between the quotes).



Step1Message = "Credit card is not known.\nCredit card number is invalid.";



//

// Step 2:

// Between the quotes, type what the alert box message shall say when

// the credit card is known and the number did not pass?

// To force a line break, use "\n" (without the quotes).

// For no message, type "" (nothing between the quotes).



Step2Message = "Credit card number is invalid.";



//

// Step 3:

// Between the quotes, type what the alert box message shall say when

// the credit card is unknown and the number passed?

// To force a line break, use "\n" (without the quotes).

// For no message, type "" (nothing between the quotes).



Step3Message = "Credit card is not known.";



//

// Step 4:

// When the credit card is known and the number passed, 

// the script can display the credit card type and the 

// number (stripped of hyphens and other non-digit characters).

// To display this message, type a Y or a y between the quotes.

// To not display this message, type "" (no space between the quotes).



DisplayAllOkayMessage = "";







////////////////////////////////////////

//                                    //

// No further customization required. //

//                                    //

////////////////////////////////////////





////////////////////////////////////////

//

//    N O T E S :

//

// Three global variables are set when function Validate() is called.

// If appropriate, your application can consult these variables:

//

// Variable Name     Value

// ^^^^^^^^^^^^^     ^^^^^

// ccType          - The name of the credit card, if determinable. 

//                   Otherwise null.

// ccNumberOkay    - Digit 1 if the credit card number is of a valid 

//                   format. Otherwise digit 0.

// ccNumberChecked - The credit card number that was checked (all spaces 

//                   and non-digit characters stripped out). Example:

//                   CC # 1234-5678-901-234 is checked as 12345678901234

//

////////////////////////////////////////







ccType = '';

ccNumberOkay = 0;

ccNumberChecked = '';



function StripNonDigits(number) {

var Re = /\d+/g;

if(Re.lastIndex > 1) { Re.lastIndex = 0; }

var Array = Re.exec(number);

if(Re.lastIndex < 1) { return 'X'; }

var ss = Array.join();

while(Re.lastIndex > 0 && Re.lastIndex < number.length) {

	Array = Re.exec(number);

	if(Array) { ss += Array.join(); }

	}

return ss;

} // StripNonDigits()





function GetType(number) {

var len = number.length;

var Re = /^5[1-5]/;

	if(Re.lastIndex > 1) { Re.lastIndex = 0; }

		var Array = Re.exec(number);

			if(Array && len == 16) { return 'MasterCard'; }

Re = /^4/;

	if(Re.lastIndex > 1) { Re.lastIndex = 0; }

		Array = Re.exec(number);

			if(Array && (len == 13 || len == 16)) { return 'Visa'; }

Re = /^3[47]/;

	if(Re.lastIndex > 1) { Re.lastIndex = 0; }

		Array = Re.exec(number);

			if(Array && len == 15) { return 'AmericanExpress'; }

Re = /^(30[0-5]|3[68])/;

	if(Re.lastIndex > 1) { Re.lastIndex = 0; }

		Array = Re.exec(number);

			if(Array && len == 14) { return 'Diners Club'; }

Re = /^6011/;

	if(Re.lastIndex > 1) { Re.lastIndex = 0; }

		Array = Re.exec(number);

			if(Array && len == 14) { return 'Discover'; }

Re = /^(3|1800|2131)/;

	if(Re.lastIndex > 1) { Re.lastIndex = 0; }

		Array = Re.exec(number);

			if(Array && (len == 15 || len == 16)) { return 'JCB'; }

return '';

} // GetType()





function Reverse(number) {

var n = '';

for(i = number.length; i >= 0; i--) { n += number.substr(i,1); }

return n;

} // Reverse()





function AddedTogether(number) {

var n = 0;

for(i = 0; i < number.length; i++) {

	var s = number.substr(i,1);

	var si = parseInt(s,10);

	if(i % 2 > 0) {

		var ii = si * 2;

		if(ii < 10) { n += ii; }

		else {

			var ss = ' ' + ii;

			for(xi = 1; xi < ss.length; xi++) {

				var xs = ss.substr(xi,1);

				var xsi = parseInt(xs,10);

				n += xsi;

				} // for

			} // else

		} // if

	else { n += si; }

	} // for

return n;

} // AddedTogether()





function Mod10(n) {

var reversed = Reverse(n);

var total = AddedTogether(reversed);

if(total % 10 > 0) { return 0; }

return 1;

} // Mod10()





function validate(n,inType) {

	ccNumberChecked = StripNonDigits(n);

	if(ccNumberChecked == 'X') {

		alert('Please supply a credit card number.');

		return false;

		}

	ccType = GetType(ccNumberChecked);

	ccNumberOkay = Mod10(ccNumberChecked);

	if ( Step1Message.length > 0 && ccType.length < 2 && ccNumberOkay == 0) { 

		alert(Step1Message); 

		return false;

	} else if ( Step2Message.length > 0 && ccNumberOkay == 0 ) { 

		alert(Step2Message); 

		return false; 

	} else if(Step3Message.length > 0 && ccType.length < 2 ) { 

		alert(Step3Message); 

		return false;

	} else if ( ccType != inType ) { //type doesn't match

		alert( "Your card number does not match card type selected." );

		return false;

	} else {

		return true;

	}

} // Validate()