// validate.js
//
// SUMMARY	
//
// This is a set of JavaScript functions for validating input on 
// an HTML form. Functions are provided to validate:
//
//		- U.S. and international phone/fax numbers
//		- U.S. ZIP codes (5 or 9 digit postal codes)
//		- U.S. Postal Codes (2 letter abbreviations for names of states)
//		- U.S. Social Security Numbers (abbreviated as SSNs)
//		- email addresses
//		- dates (entry of year, month, and day and validity of combined date)
//		- credit card numbers
//
// Supporting utility functions validate that:
//
//		- characters are Letter, Digit, or LetterOrDigit
//		- strings are a Signed, Positive, Negative, Nonpositive, or Nonnegative integer
//		- strings are a Float or a SignedFloat
//		- strings are Alphabetic, Alphanumeric, or Whitespace
//		- strings contain an integer within a specified range
//
// Functions are also provided to interactively check the
// above kinds of data and prompt the user if they have
// been entered incorrectly.
//
// Other utility functions are provided to:
//
// 	- remove from a string characters which are/are not 
//		in a "bag" of selected characters	
// 	- reformat a string, adding delimiter characters
//	- strip whitespace/leading whitespace from a string
//	- reformat U.S. phone numbers, ZIP codes, and Social Security numbers
//
//
// Many of the below functions take an optional parameter eok (for "emptyOK")
// which determines whether the empty string will return true or false.
// Default behavior is controlled by global variable defaultEmptyOK.
//
// BASIC DATA VALIDATION FUNCTIONS:
//
// isWhitespace (s)					Check whether string s is empty or whitespace.
// isLetter (c)						Check whether character c is an English letter 
// isDigit (c)						Check whether character c is a digit 
// isLetterOrDigit (c)				Check whether character c is a letter or digit.
// isInteger (s [,eok])				True if all characters in string s are numbers.
// isSignedInteger (s [,eok])		True if all characters in string s are numbers; leading + or - allowed.
// isPositiveInteger (s [,eok])		True if string s is an integer > 0.
// isNonnegativeInteger (s [,eok])	True if string s is an integer >= 0.
// isNegativeInteger (s [,eok])		True if s is an integer < 0.
// isNonpositiveInteger (s [,eok])	True if s is an integer <= 0.
// isFloat (s [,eok])				True if string s is an unsigned floating point (real) number. (Integers also OK.)
// isSignedFloat (s [,eok])			True if string s is a floating point number; leading + or - allowed. (Integers also OK.)
// isAlphabetic (s [,eok])			True if string s is English letters 
// isAlphanumeric (s [,eok])		True if string s is English letters and numbers only.
// 
// isSSN (s [,eok])					True if string s is a valid U.S. Social Security Number.
// isUSPhoneNumber (s [,eok])		True if string s is a valid U.S. Phone Number. 
// isInternationalPhoneNumber (s [,eok]) True if string s is a valid international phone number.
// isDUNSNumber (s [,eok])			True if string s is a valid DUNS Number.
// isGiftCardNumber (s [,eok])		True if string s is a valid Gift Card Number.
// isFreqDinerNumber (s [,eok])		True if string s is a valid Frequent Diner Card Number.
// isZIPCode (s [,eok])				True if string s is a valid U.S. ZIP code.
// isStateCode (s [,eok])			True if string s is a valid U.S. Postal Code
// isEmail (s [,eok])				True if string s is a valid email address.
// isEmails (s [,sep])				True if string s is a valid email address (or multiple separate by [sep] default=",").
// isYear (s [,eok])				True if string s is a valid Year number.
// isIntegerInRange (s, a, b [,eok])True if string s is an integer between a and b, inclusive.
// isMonth (s [,eok])				True if string s is a valid month between 1 and 12.
// isDay (s [,eok])					True if string s is a valid day between 1 and 31.
// daysInFebruary (year)			Returns number of days in February of that year.
// isDate (year, month, day)		True if string arguments form a valid date.
//
// FUNCTIONS TO REFORMAT DATA:
//
// stripCharsInBag (s, bag)			Removes all characters in string bag from string s.
// stripCharsNotInBag (s, bag)		Removes all characters NOT in string bag from string s.
// stripWhitespace (s)				Removes all whitespace characters from s.
// stripInitialWhitespace (s)		Removes initial (leading) whitespace characters from s.
// reformat (TARGETSTRING, STRING,	Function for inserting formatting characters or
//	INTEGER, STRING, INTEGER ... )		delimiters into TARGETSTRING.								
// reformatZIPCode (ZIPString)		If 9 digits, inserts separator hyphen.
// reformatGiftCardNumber (GiftCard#)Reformats as 1234-1234-1234-1234
// reformatFreqDinerNumber (FreqDiner#)Reformats as 1234-1234-1234-1234
// reformatSSN (SSN)				Reformats as 123-45-6789.
// reformatUSPhone (USPhone)		Reformats as (123) 456-789.
//
// FUNCTIONS TO PROMPT USER:
//
// prompt (s)						Display prompt string s in status bar.
// promptEntry (s)					Display data entry prompt string s in status bar.
// warnEmpty (theField, s)			Notify user that required field theField is empty.
// warnInvalid (theField, s)		Notify user that contents of field theField are invalid.
//
// FUNCTIONS TO INTERACTIVELY CHECK FIELD CONTENTS:
//
// checkString (theField, s [,eok])	Check that theField.value is not empty or all whitespace.
// checkLength (theField, s, len [,eok])Check that theField.value is <= length
// checkFloat (theField, s [,eok])	Check that theField.value is a valid Float. 
// checkInteger (theField, s [,eok])Check that theField.value is a valid Integer. 
// checkStateCode (theField)		Check that theField.value is a valid U.S. state code.
// checkDUNSNumber (theField [,eok])Check that theField.value is a valid DUNS number.
// checkGiftCardNumber (theField [,eok])Check that theField.value is a valid Gift Card number.
// checkFreqDinerNumber (theField [,eok])Check that theField.value is a valid Frequent Diner Card number.
// checkZIPCode (theField [,eok])	Check that theField.value is a valid ZIP code.
// checkUSPhone (theField [,eok])	Check that theField.value is a valid US Phone.
// checkInternationalPhone (theField [,eok]) Check that theField.value is a valid International Phone.
// checkEmail (theField [,eok])		Check that theField.value is a valid Email.
// checkSSN (theField [,eok])		Check that theField.value is a valid SSN.
// checkYear (theField [,eok])		Check that theField.value is a valid Year.
// checkMonth (theField [,eok])		Check that theField.value is a valid Month.
// checkDay (theField [,eok])		Check that theField.value is a valid Day.
// checkDate (yearField, monthField, dayField, labelString, OKtoOmitDay)
//									Check that field values form a valid date.
// checkCreditCard (radio, theField)Validate credit card info.
//
// CREDIT CARD DATA VALIDATION FUNCTIONS
// 
// isCreditCard (st)				True if credit card number passes the Luhn Mod-10 test.
// isVisa (cc)						True if string cc is a valid VISA number.
// isMasterCard (cc)				True if string cc is a valid MasterCard number.
// isAmericanExpress (cc)			True if string cc is a valid American Express number.
// isDinersClub (cc)				True if string cc is a valid Diner's Club number.
// isCarteBlanche (cc)				True if string cc is a valid Carte Blanche number.
// isDiscover (cc)					True if string cc is a valid Discover card number.
// isEnRoute (cc)					True if string cc is a valid enRoute card number.
// isJCB (cc)						True if string cc is a valid JCB card number.
// isAnyCard (cc)					True if string cc is a valid card number for any of the accepted types.
// isCardMatch (Type, Number)		True if Number is valid for credic card of type Type.
//

var digits = "0123456789";
var lowercaseLetters = "abcdefghijklmnopqrstuvwxyz";
var uppercaseLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var whitespace = " \t\n\r";
var decimalPointDelimiter = ".";
var phoneNumberDelimiters = "()- ";
var validUSPhoneChars = digits + phoneNumberDelimiters;
var validWorldPhoneChars = digits + phoneNumberDelimiters + "+";
var SSNDelimiters = "- ";
var validSSNChars = digits + SSNDelimiters;
var digitsInSocialSecurityNumber = 9;
var digitsInUSPhoneNumber = 10;
var ZIPCodeDelimiters = "- ";
var DUNSNumberDelimiters = "- ";
var GiftCardNumberDelimiters = "- ";
var FreqDinerNumberDelimiters = "- ";
var validZIPCodeChars = digits + ZIPCodeDelimiters;
var digitsInDUNSNumber = 9;
var digitsInGiftCardNumber = 16;
var digitsInFreqDinerNumber = 16;
var digitsInZIPCode1 = 5;
var digitsInZIPCode2 = 9;
var creditCardDelimiters = " ";

// CONSTANT STRING DECLARATIONS
// m is an abbreviation for "missing"
var mPrefix = "You did not enter a value into the '";
var mSuffix = "' field. This is a required field. Please enter it now.";

// s is an abbreviation for "string"
var sUSLastName = "Last Name";
var sUSFirstName = "First Name";
var sWorldLastName = "Family Name";
var sWorldFirstName = "Given Name";
var sTitle = "Title";
var sCompanyName = "Company Name";
var sUSAddress = "Street Address";
var sWorldAddress = "Address";
var sCity = "City";
var sStateCode = "State Code";
var sWorldState = "State, Province, or Prefecture";
var sCountry = "Country";
var sZIPCode = "ZIP Code";
var sWorldPostalCode = "Postal Code";
var sPhone = "Phone Number";
var sFax = "Fax Number";
var sDateOfBirth = "Date of Birth";
var sExpirationDate = "Expiration Date";
var sEmail = "Email";
var sSSN = "Social Security Number";
var sCreditCardNumber = "Credit Card Number";
var sOtherInfo = "Other Information";

// i is an abbreviation for "invalid"
var iStateCode = "This field must be a valid two character U.S. state abbreviation (like CA for California). Please reenter it now.";
var iDUNSNumber = "This field must be a valid 9 digit DUNS number (like 123456789). Please reenter it now."; 
var iGiftCardNumber = "This account must be a valid 16 digit Gift Card number (like 1234-1234-1234-1234). Please reenter it now."; 
var iFreqDinerNumber = "This account must be a valid 16 digit Frequent Diner Card number (like 1234-1234-1234-1234). Please reenter it now."; 
var iZIPCode = "This field must be a 5 or 9 digit U.S. ZIP Code (like 94043). Please reenter it now.";
var iUSPhone = "This field must be a 10 digit U.S. phone number (like 415 555 1212). Please reenter it now.";
var iWorldPhone = "This field must be a valid international phone number. Please reenter it now.";
var iSSN = "This field must be a 9 digit U.S. social security number (like 123 45 6789). Please reenter it now.";
var iEmail = "This field must be a valid email address (like foo@bar.com). Please reenter it now.";
var iCreditCardPrefix = "This is not a valid ";
var iCreditCardSuffix = " credit card number. (Click the link on this form to see a list of sample numbers.) Please reenter it now.";
var iDay = "This field must be a day number between 1 and 31. Please reenter it now.";
var iMonth = "This field must be a month number between 1 and 12. Please reenter it now.";
var iYear = "This field must be a 2 or 4 digit year number. Please reenter it now.";
var iDatePrefix = "The Day, Month, and Year for ";
var iDateSuffix = " do not form a valid date. Please reenter them now.";
var iLength = "The '%1' field must contain less than %2 characters. Please reenter it now.";
var iNumber = "The '%1' field must contain a number. Please reenter it now.";

// p is an abbreviation for "prompt"
var pEntryPrompt = "Please enter a ";
var pStateCode = "2 character code (like CA).";
var pZIPCode = "5 or 9 digit U.S. ZIP Code (like 94043).";
var pUSPhone = "10 digit U.S. phone number (like 415 555 1212).";
var pWorldPhone = "international phone number.";
var pSSN = "9 digit U.S. social security number (like 123 45 6789).";
var pEmail = "valid email address (like foo@bar.com).";
var pCreditCard = "valid credit card number.";
var pDay = "day number between 1 and 31.";
var pMonth = "month number between 1 and 12.";
var pYear = "2 or 4 digit year number.";

// Global variable defaultEmptyOK defines default return value 
// for many functions when they are passed the empty string. 
// By default, they will return defaultEmptyOK.
//
// defaultEmptyOK is false, which means that by default, 
// these functions will do "strict" validation. Function
// isInteger, for example, will only return true if it is
// passed a string containing an integer; if it is passed
// the empty string, it will return false.
//
// You can change this default behavior globally (for all 
// functions which use defaultEmptyOK) by changing the value
// of defaultEmptyOK.
//
// Most of these functions have an optional argument emptyOK
// which allows you to override the default behavior for 
// the duration of a function call.
//
// This functionality is useful because it is possible to
// say "if the user puts anything in this field, it must
// be an integer (or a phone number, or a string, etc.), 
// but it's OK to leave the field empty too."
// This is the case for fields which are optional but which
// must have a certain kind of content if filled in.

var defaultEmptyOK = false;

// Valid U.S. Postal Codes for states, territories, armed forces, etc.
// See http://www.usps.gov/ncsc/lookups/abbr_state.txt.

var USStateCodeDelimiter = "|";
var USStateCodes = "AL|AK|AS|AZ|AR|CA|CO|CT|DE|DC|FM|FL|GA|GU|HI|ID|IL|IN|IA|KS|KY|LA|ME|MH|MD|MA|MI|MN|MS|MO|MT|NE|NV|NH|NJ|NM|NY|NC|ND|MP|OH|OK|OR|PW|PA|PR|RI|SC|SD|TN|TX|UT|VT|VI|VA|WA|WV|WI|WY|AE|AA|AE|AE|AP";

// Check whether string s is empty.
function isEmpty(s)
{
	return ((s == null) || (s.length == 0));
}

// Returns true if string s is empty or whitespace characters only.
function isWhitespace (s)
{
	var i;

	// Is s empty?
	if (isEmpty(s)) 
		return true;

	// Search through string's characters one by one
	// until we find a non-whitespace character.
	// When we do, return false; if we don't, return true.

	for (i = 0; i < s.length; i++)
	{
		// Check that current character isn't whitespace.
		var c = s.charAt(i);

		if (whitespace.indexOf(c) == -1) 
			return false;
	}
	// All characters are whitespace.
	return true;
}

// Removes all characters which appear in string bag from string s.
function stripCharsInBag (s, bag)
{
	var i;
	var returnString = "";

	for (i = 0; i < s.length; i++)
	{
		var c = s.charAt(i);
		if (bag.indexOf(c) == -1)
			returnString += c;
	}
	return returnString;
}

// Removes all characters which do NOT appear in string bag from string s.
function stripCharsNotInBag (s, bag)
{
	var i;
	var returnString = "";

	for (i = 0; i < s.length; i++)
	{
		var c = s.charAt(i);
		if (bag.indexOf(c) != -1)
			returnString += c;
	}
	return returnString;
}

// Removes all whitespace characters from s.
// Global variable whitespace (see above)defines which characters are considered whitespace.
function stripWhitespace (s)
{
	return stripCharsInBag (s, whitespace);
}

// Removes initial (leading) whitespace characters from s.
// Global variable whitespace (see above) defines which characters are considered whitespace.
function stripInitialWhitespace (s)
{
	var i = 0;

	while ((i < s.length) && indexOf(s.charAt(i), whitespace))
		i++;
	
	return s.substring (i, s.length);
}

// Returns true if character c is an English letter (A .. Z, a..z).
//
// NOTE: Need i18n version to support European characters.
// This could be tricky due to different character
// sets and orderings for various languages and platforms.

function isLetter (c)
{
	return (((c >= "a") && (c <= "z")) || ((c >= "A") && (c <= "Z")))
}

// Returns true if character c is a digit (0 .. 9).
function isDigit (c)
{
	return ((c >= "0") && (c <= "9"));
}

// Returns true if character c is a letter or digit.
function isLetterOrDigit (c)
{
	return (isLetter(c) || isDigit(c));
}

// isInteger (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if all characters in string s are numbers.
//
// Accepts non-signed integers only. Does not accept floating 
// point, exponential notation, etc.
//
// We don't use parseInt because that would accept a string
// with trailing non-numeric characters.
//
// By default, returns defaultEmptyOK if s is empty.
// There is an optional second argument called emptyOK.
// emptyOK is used to override for a single function call
//		the default behavior which is specified globally by
//		defaultEmptyOK.
// If emptyOK is false (or any value other than true), 
//		the function will return false if s is empty.
// If emptyOK is true, the function will return true if s is empty.
//
// EXAMPLE FUNCTION CALL:	RESULT:
// isInteger ("5")			true 
// isInteger ("")			defaultEmptyOK
// isInteger ("-5")			false
// isInteger ("", true)		true
// isInteger ("", false)	false
// isInteger ("5", false)	true

function isInteger (s)
{
	var i;

	if (isEmpty(s)) 
	{
		if (isInteger.arguments.length == 1)
			return defaultEmptyOK;
		else 
			return (isInteger.arguments[1] == true);
	}
	// Search through string's characters one by one
	// until we find a non-numeric character.
	// When we do, return false; if we don't, return true.
	for (i = 0; i < s.length; i++)
	{
		// Check that current character is number.
		var c = s.charAt(i);

		if (!isDigit(c))
			return false;
	}
	// All characters are numbers.
	return true;
}

// isSignedInteger (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if all characters are numbers; 
// first character is allowed to be + or - as well.
//
// Does not accept floating point, exponential notation, etc.
//
// We don't use parseInt because that would accept a string
// with trailing non-numeric characters.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
//
// EXAMPLE FUNCTION CALL:		RESULT:
// isSignedInteger ("5")		true 
// isSignedInteger ("")			defaultEmptyOK
// isSignedInteger ("-5")		true
// isSignedInteger ("+5")		true
// isSignedInteger ("", false)	false
// isSignedInteger ("", true)	true
function isSignedInteger (s)
{
	if (isEmpty(s))
	{
		if (isSignedInteger.arguments.length == 1)
			return defaultEmptyOK;
		else 
			return (isSignedInteger.arguments[1] == true);
	}
	else
	{
		var startPos = 0;
		var secondArg = defaultEmptyOK;

		if (isSignedInteger.arguments.length > 1)
			secondArg = isSignedInteger.arguments[1];

		// skip leading + or -
		if ((s.charAt(0) == "-") || (s.charAt(0) == "+"))
			startPos = 1;	
		return (isInteger(s.substring(startPos, s.length), secondArg));
	}
}

// isPositiveInteger (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if string s is an integer > 0.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isPositiveInteger (s)
{
	var secondArg = defaultEmptyOK;

	if (isPositiveInteger.arguments.length > 1)
		secondArg = isPositiveInteger.arguments[1];

	// The next line is a bit byzantine. What it means is:
	// a) s must be a signed integer, AND
	// b) one of the following must be true:
	//	i)	s is empty and we are supposed to return true for
	//		empty strings
	//	ii) this is a positive, not negative, number

	return (isSignedInteger(s, secondArg) && ((isEmpty(s) && secondArg)	|| (parseInt (s) > 0)));
}

// isNonnegativeInteger (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if string s is an integer >= 0.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isNonnegativeInteger (s)
{
	var secondArg = defaultEmptyOK;

	if (isNonnegativeInteger.arguments.length > 1)
		secondArg = isNonnegativeInteger.arguments[1];

	// The next line is a bit byzantine. What it means is:
	// a) s must be a signed integer, AND
	// b) one of the following must be true:
	//	i)	s is empty and we are supposed to return true for
	//		empty strings
	//	ii) this is a number >= 0

	return (isSignedInteger(s, secondArg) && ((isEmpty(s) && secondArg)	|| (parseInt (s) >= 0)));
}

// isNegativeInteger (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if string s is an integer < 0.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.

function isNegativeInteger (s)
{
	var secondArg = defaultEmptyOK;

	if (isNegativeInteger.arguments.length > 1)
		secondArg = isNegativeInteger.arguments[1];

	// The next line is a bit byzantine. What it means is:
	// a) s must be a signed integer, AND
	// b) one of the following must be true:
	//	i)	s is empty and we are supposed to return true for
	//		empty strings
	//	ii) this is a negative, not positive, number

	return (isSignedInteger(s, secondArg) && ((isEmpty(s) && secondArg)	|| (parseInt (s) < 0)));
}

// isNonpositiveInteger (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if string s is an integer <= 0.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isNonpositiveInteger (s)
{
	var secondArg = defaultEmptyOK;

	if (isNonpositiveInteger.arguments.length > 1)
		secondArg = isNonpositiveInteger.arguments[1];

	// The next line is a bit byzantine. What it means is:
	// a) s must be a signed integer, AND
	// b) one of the following must be true:
	//	i)	s is empty and we are supposed to return true for
	//		empty strings
	//	ii) this is a number <= 0

	return (isSignedInteger(s, secondArg) && ((isEmpty(s) && secondArg)	|| (parseInt (s) <= 0)));
}

// isFloat (STRING s [, BOOLEAN emptyOK])
// 
// True if string s is an unsigned floating point (real) number. 
//
// Also returns true for unsigned integers. If you wish
// to distinguish between integers and floating point numbers,
// first call isInteger, then call isFloat.
//
// Does not accept exponential notation.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isFloat (s)
{
	var i;
	var seenDecimalPoint = false;

	if (isEmpty(s))
	{
		if (isFloat.arguments.length == 1)
			return defaultEmptyOK;
		else 
			return (isFloat.arguments[1] == true);
	}
	if (s == decimalPointDelimiter)
		return false;

	// Search through string's characters one by one
	// until we find a non-numeric character.
	// When we do, return false; if we don't, return true.

	for (i = 0; i < s.length; i++)
	{
		// Check that current character is number.
		var c = s.charAt(i);

		if ((c == decimalPointDelimiter) && !seenDecimalPoint)
			seenDecimalPoint = true;
		else
		{
			if (!isDigit(c)) 
				return false;
		}
	}
	return true;
}

// isSignedFloat (STRING s [, BOOLEAN emptyOK])
// 
// True if string s is a signed or unsigned floating point 
// (real) number. First character is allowed to be + or -.
//
// Also returns true for unsigned integers. If you wish
// to distinguish between integers and floating point numbers,
// first call isSignedInteger, then call isSignedFloat.
//
// Does not accept exponential notation.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isSignedFloat (s)
{
	if (isEmpty(s))
	{
		if (isSignedFloat.arguments.length == 1)
			return defaultEmptyOK;
		else
			return (isSignedFloat.arguments[1] == true);
	}
	else
	{
		var startPos = 0;
		var secondArg = defaultEmptyOK;

		if (isSignedFloat.arguments.length > 1)
			secondArg = isSignedFloat.arguments[1];

		// skip leading + or -
		if ((s.charAt(0) == "-") || (s.charAt(0) == "+"))
			startPos = 1;	
		return (isFloat(s.substring(startPos, s.length), secondArg));
	}
}

// isAlphabetic (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if string s is English letters 
// (A .. Z, a..z) only.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
//
// NOTE: Need i18n version to support European characters.
// This could be tricky due to different character
// sets and orderings for various languages and platforms.
function isAlphabetic (s)
{
	var i;

	if (isEmpty(s)) 
	{
		if (isAlphabetic.arguments.length == 1)
			return defaultEmptyOK;
		else 
			return (isAlphabetic.arguments[1] == true);
	}
	// Search through string's characters one by one
	// until we find a non-alphabetic character.
	// When we do, return false; if we don't, return true.
	for (i = 0; i < s.length; i++)
	{
		// Check that current character is letter.
		var c = s.charAt(i);

		if (!isLetter(c))
			return false;
	}
	// All characters are letters.
	return true;
}

// isAlphanumeric (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if string s is English letters 
// (A .. Z, a..z) and numbers only (0 .. 9).
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
//
// NOTE: Need i18n version to support European characters.
// This could be tricky due to different character
// sets and orderings for various languages and platforms.
function isAlphanumeric (s)
{
	var i;

	if (isEmpty(s))
	{
		if (isAlphanumeric.arguments.length == 1)
			return defaultEmptyOK;
		else 
			return (isAlphanumeric.arguments[1] == true);
	}
	// Search through string's characters one by one
	// until we find a non-alphanumeric character.
	// When we do, return false; if we don't, return true.
	for (i = 0; i < s.length; i++)
	{
		// Check that current character is number or letter.
		var c = s.charAt(i);

		if (! (isLetter(c) || isDigit(c)))
			return false;
	}
	// All characters are numbers or letters.
	return true;
}

// reformat (TARGETSTRING, STRING, INTEGER, STRING, INTEGER ... )
//
// Handy function for arbitrarily inserting formatting characters
// or delimiters of various kinds within TARGETSTRING.
//
// reformat takes one named argument, a string s, and any number
// of other arguments. The other arguments must be integers or
// strings. These other arguments specify how string s is to be
// reformatted and how and where other strings are to be inserted
// into it.
//
// reformat processes the other arguments in order one by one.
// * If the argument is an integer, reformat appends that number 
//		of sequential characters from s to the resultString.
// * If the argument is a string, reformat appends the string
//		to the resultString.
//
// NOTE: The first argument after TARGETSTRING must be a string.
// (It can be empty.)	The second argument must be an integer.
// Thereafter, integers and strings must alternate. This is to
// provide backward compatibility to Navigator 2.0.2 JavaScript
// by avoiding use of the typeof operator.
//
// It is the caller's responsibility to make sure that we do not
// try to copy more characters from s than s.length.
//
// EXAMPLES:
//
// * To reformat a 10-digit U.S. phone number from "1234567890"
//		to "(123) 456-7890" make this function call:
//		reformat("1234567890", "(", 3, ") ", 3, "-", 4)
//
// * To reformat a 9-digit U.S. Social Security number from
//		"123456789" to "123-45-6789" make this function call:
//		reformat("123456789", "", 3, "-", 2, "-", 4)
//
// HINT:
//
// If you have a string which is already delimited in one way
// (example: a phone number delimited with spaces as "123 456 7890")
// and you want to delimit it in another way using function reformat,
// call function stripCharsNotInBag to remove the unwanted 
// characters, THEN call function reformat to delimit as desired.
//
// EXAMPLE:
//
// reformat (stripCharsNotInBag ("123 456 7890", digits), "(", 3, ") ", 3, "-", 4)
function reformat (s)
{
	var arg;
	var sPos = 0;
	var resultString = "";

	for (var i = 1; i < reformat.arguments.length; i++)
	{
		arg = reformat.arguments[i];
		if (i % 2 == 1) 
			resultString += arg;
		else
		{
			resultString += s.substring(sPos, sPos + arg);
			sPos += arg;
		}
	}
	return resultString;
}

// isSSN (STRING s [, BOOLEAN emptyOK])
// 
// isSSN returns true if string s is a valid U.S. Social
// Security Number. Must be 9 digits.
//
// NOTE: Strip out any delimiters (spaces, hyphens, etc.)
// from string s before calling this function.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isSSN (s)
{
	if (isEmpty(s)) 
	{
		if (isSSN.arguments.length == 1) 
			return defaultEmptyOK;
		else 
			return (isSSN.arguments[1] == true);
	}
	return (isInteger(s) && s.length == digitsInSocialSecurityNumber);
}

// isUSPhoneNumber (STRING s [, BOOLEAN emptyOK])
// 
// isUSPhoneNumber returns true if string s is a valid U.S. Phone
// Number. Must be 10 digits.
//
// NOTE: Strip out any delimiters (spaces, hyphens, parentheses, etc.)
// from string s before calling this function.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isUSPhoneNumber (s)
{
	if (isEmpty(s)) 
	{
		if (isUSPhoneNumber.arguments.length == 1)
			return defaultEmptyOK;
		else 
			return (isUSPhoneNumber.arguments[1] == true);
	}
	return (isInteger(s) && s.length == digitsInUSPhoneNumber);
}

// isInternationalPhoneNumber (STRING s [, BOOLEAN emptyOK])
// 
// isInternationalPhoneNumber returns true if string s is a valid 
// international phone number. Must be digits only; any length OK.
// May be prefixed by + character.
//
// NOTE: A phone number of all zeros would not be accepted.
// I don't think that is a valid phone number anyway.
//
// NOTE: Strip out any delimiters (spaces, hyphens, parentheses, etc.)
// from string s before calling this function. You may leave in 
// leading + character if you wish.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isInternationalPhoneNumber (s)
{
	if (isEmpty(s)) 
	{
		if (isInternationalPhoneNumber.arguments.length == 1)
			return defaultEmptyOK;
		else
			return (isInternationalPhoneNumber.arguments[1] == true);
	}
	return (isPositiveInteger(s));
}

// isDUNSNumber (STRING s [, BOOLEAN emptyOK])
// 
// isDUNSNumber returns true if string s is a valid 
// DUNS Number. Must be 9 digits only.
//
// NOTE: Strip out any delimiters (spaces, etc.)
// from string s before calling this function. 
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isDUNSNumber (s)
{
	if (isEmpty(s))
	{
		if (isDUNSNumber.arguments.length == 1) 
			return defaultEmptyOK;
		else return (isDUNSNumber.arguments[1] == true);
	}
	return (isInteger(s) && (s.length == digitsInDUNSNumber));
}

// isGiftCardNumber (STRING s [, BOOLEAN emptyOK])
// 
// isGiftCardNumber returns true if string s is a valid 
// Gift Card Number. Must be 16 digits only.
//
// NOTE: Strip out any delimiters (spaces, etc.)
// from string s before calling this function. 
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isGiftCardNumber (s)
{
	if (isEmpty(s))
	{
		if (isGiftCardNumber.arguments.length == 1) 
			return defaultEmptyOK;
		else return (isGiftCardNumber.arguments[1] == true);
	}
	return (isInteger(s) && (s.length == digitsInGiftCardNumber));
}

// isFreqDinerNumber (STRING s [, BOOLEAN emptyOK])
// 
// isFreqDinerNumber returns true if string s is a valid 
// Frequent Diner card Number. Must be 16 digits only.
//
// NOTE: Strip out any delimiters (spaces, etc.)
// from string s before calling this function. 
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isFreqDinerNumber (s)
{
	if (isEmpty(s))
	{
		if (isFreqDinerNumber.arguments.length == 1) 
			return defaultEmptyOK;
		else return (isFreqDinerNumber.arguments[1] == true);
	}
	return (isInteger(s) && (s.length == digitsInFreqDinerNumber));
}

// isZIPCode (STRING s [, BOOLEAN emptyOK])
// 
// isZIPCode returns true if string s is a valid 
// U.S. ZIP code. Must be 5 or 9 digits only.
//
// NOTE: Strip out any delimiters (spaces, hyphens, etc.)
// from string s before calling this function. 
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isZIPCode (s)
{
	if (isEmpty(s))
	{
		if (isZIPCode.arguments.length == 1) 
			return defaultEmptyOK;
		else return (isZIPCode.arguments[1] == true);
	}
	return (isInteger(s) && ((s.length == digitsInZIPCode1) || (s.length == digitsInZIPCode2)));
}

// isStateCode (STRING s [, BOOLEAN emptyOK])
// 
// Return true if s is a valid U.S. Postal Code 
// (abbreviation for state).
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isStateCode(s)
{
	if (isEmpty(s))
	{
		if (isStateCode.arguments.length == 1)
			return defaultEmptyOK;
		else
			return (isStateCode.arguments[1] == true);
	}
	return ((USStateCodes.indexOf(s) != -1) && (s.indexOf(USStateCodeDelimiter) == -1));
}

// isEmail (STRING s [, BOOLEAN emptyOK])
// 
// Email address must be of form a@b.c -- in other words:
// * there must be at least one character before the @
// * there must be at least one character before and after the .
// * the characters @ and . are both required
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isEmail (s)
{
	if (isEmpty(s))
	{
		if (isEmail.arguments.length == 1)
			return defaultEmptyOK;
		else 
			return (isEmail.arguments[1] == true);
	}
	// is s all whitespace?
	if (isWhitespace(s))
		return false;

	// clear out any leading or trailing spaces
	s = trim(s);

	// is there any whitespace in the address?
	var tmp = stripWhitespace(s);
	if (tmp.length != s.length)
		return false;
	
	// there must be >= 1 character before @, so we
	// start looking at character position 1 
	// (i.e. second character)
	var i = 1;
	var sLength = s.length;

	// look for @
	while ((i < sLength) && (s.charAt(i) != "@"))
		i++

	if ((i >= sLength) || (s.charAt(i) != "@"))
		return false;
	else
		i += 2;

	// look for .
	while ((i < sLength) && (s.charAt(i) != "."))
		i++

	// there must be at least one character after the .
	if ((i >= sLength - 1) || (s.charAt(i) != "."))
		return false;
	else
		return true;
}

// isEmails (STRING s [, STRING sep])
// 
// Email address must be of form a@b.c -- in other words:
// * there must be at least one character before the @
// * there must be at least one character before and after the .
// * the characters @ and . are both required
//
// optional argument sep default to (,)
function isEmails (s, sep)
{
	if (isEmails.arguments.length == 1) 
		sep = ",";

	var tmp = s.split(sep);
	
	for (var i = 0; i < tmp.length; i++)
	{
		if (!isEmail(tmp[i]))
			return false;
	}
	return true;
}

// isYear (STRING s [, BOOLEAN emptyOK])
// 
// isYear returns true if string s is a valid 
// Year number. Must be 2 or 4 digits only.
// 
// For Year 2000 compliance, you are advised
// to use 4-digit year numbers everywhere.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isYear (s)
{
	if (isEmpty(s))
	{
		if (isYear.arguments.length == 1)
			return defaultEmptyOK;
		else
			return (isYear.arguments[1] == true);
	}
	if (!isNonnegativeInteger(s)) 
		return false;
	return ((s.length == 2) || (s.length == 4));
}

// isIntegerInRange (STRING s, INTEGER a, INTEGER b [, BOOLEAN emptyOK])
// 
// isIntegerInRange returns true if string s is an integer 
// within the range of integer arguments a and b, inclusive.
// 
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isIntegerInRange (s, a, b)
{
	if (isEmpty(s))
	{
		if (isIntegerInRange.arguments.length == 1)
			return defaultEmptyOK;
		else
			return (isIntegerInRange.arguments[1] == true);
	}
	// Catch non-integer strings to avoid creating a NaN below,
	// which isn't available on JavaScript 1.0 for Windows.
	if (!isInteger(s, false))
		return false;

	// Now, explicitly change the type to integer via parseInt
	// so that the comparison code below will work both on 
	// JavaScript 1.2 (which typechecks in equality comparisons)
	// and JavaScript 1.1 and before (which doesn't).
	var num = parseInt (s);
	return ((num >= a) && (num <= b));
}

// isMonth (STRING s [, BOOLEAN emptyOK])
// 
// isMonth returns true if string s is a valid 
// month number between 1 and 12.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isMonth (s)
{
	if (isEmpty(s))
	{
		if (isMonth.arguments.length == 1)
			return defaultEmptyOK;
		else
			return (isMonth.arguments[1] == true);
	}
	return isIntegerInRange (s, 1, 12);
}

// isDay (STRING s [, BOOLEAN emptyOK])
// 
// isDay returns true if string s is a valid 
// day number between 1 and 31.
// 
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function isDay (s)
{
	if (isEmpty(s))
	{
		if (isDay.arguments.length == 1)
			return defaultEmptyOK;
		else	
			return (isDay.arguments[1] == true);
	}
	return isIntegerInRange (s, 1, 31);
}

// daysInFebruary (INTEGER year)
// 
// Given integer argument year,
// returns number of days in February of that year.
function daysInFebruary (year)
{	// February has 29 days in any year evenly divisible by four,
	// EXCEPT for centurial years which are not also divisible by 400.
	return (((year % 4 == 0) && ((!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28 );
}

// isDate (STRING year, STRING month, STRING day)
//
// isDate returns true if string arguments year, month, and day 
// form a valid date.
// 
function isDate (year, month, day)
{
	return validDate(month + "/" + day + "/" + year);
}

/* FUNCTIONS TO NOTIFY USER OF INPUT REQUIREMENTS OR MISTAKES. */
// Display prompt string s in status bar.
function prompt (s)
{
	window.status = s;
}

// Display data entry prompt string s in status bar.
function promptEntry (s)
{
	window.status = pEntryPrompt + s;
}

// Notify user that required field theField is empty.
// String s describes expected contents of theField.value.
// Put focus in theField and return false.
function warnEmpty (theField, s)
{
	theField.focus();
	alert(mPrefix + s + mSuffix);
	return false;
}

// Notify user that contents of field theField are invalid.
// String s describes expected contents of theField.value.
// Put select theField, pu focus in it, and return false.
function warnInvalid (theField, s)
{
	theField.focus();
	theField.select();
	alert(s);
	return false;
}

// Notify user that required field theField has too many characters.
// String s describes expected contents of theField.value.
// Put focus in theField and return false.
function warnLength (theField, s, len)
{
	var tmp = iLength;
	tmp = tmp.replace(/%1/, s);
	tmp = tmp.replace(/%2/, len);

	theField.focus();
	theField.select();
	alert(tmp);
	return false;
}

// Notify user that required field theField is not the correct format.
// String s describes expected contents of theField.value.
// Put focus in theField and return false.
function warnNumber (theField, s)
{
	var tmp = iNumber;
	tmp = tmp.replace(/%1/, s);

	theField.focus();
	theField.select();
	alert(tmp);
	return false;
}

/* FUNCTIONS TO INTERACTIVELY CHECK VARIOUS FIELDS. */
// checkString (TEXTFIELD theField, STRING s, [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is not all whitespace.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkString (theField, s, emptyOK)
{
	if (checkString.arguments.length == 2) 
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	if (isWhitespace(theField.value)) 
		return warnEmpty (theField, s);
	else return true;
}

// checkLength (TEXTFIELD theField, STRING s, INT len, [, BOOLEAN emptyOK==false])
//
// Check that string theField.value has a length <= len
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkLength (theField, s, len, emptyOK)
{
	if (checkLength.arguments.length == 3) 
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	if (theField.value.length > len) 
		return warnLength (theField, s, len);
	else return true;
}

// checkFloat (TEXTFIELD theField, STRING s, [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a Float
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkFloat (theField, s, emptyOK)
{
	if (checkFloat.arguments.length == 2) 
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	if (!isFloat(theField.value))
		return warnNumber (theField, s);
	else return true;
}

// checkInteger (TEXTFIELD theField, STRING s, [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a Float
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkInteger (theField, s, emptyOK)
{
	if (checkInteger.arguments.length == 2) 
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	if (!isInteger(theField.value))
		return warnNumber (theField, s);
	else return true;
}

// checkStateCode (TEXTFIELD theField [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a valid U.S. state code.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkStateCode (theField, emptyOK)
{
	if (checkStateCode.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else
	{
		theField.value = theField.value.toUpperCase();
		if (!isStateCode(theField.value, false)) 
			return warnInvalid (theField, iStateCode);
		else
			return true;
	}
}

// takes GiftCardNum, a string of 16 digits;
function reformatGiftCardNumber (GiftCardNum)
{
	return(reformat (GiftCardNum, "", 4, "-", 4, "-", 4, "-", 4));
}

// takes FreqDinerNum, a string of 19 digits;
function reformatFreqDinerNumber (FreqDinerNum)
{
	return(reformat (FreqDinerNum, "", 4, "-", 4, "-", 4, "-", 4));
}

// takes ZIPString, a string of 5 or 9 digits;
// if 9 digits, inserts separator hyphen
function reformatZIPCode (ZIPString)
{
	if (ZIPString.length == 5)
		return ZIPString;
	else
		return(reformat (ZIPString, "", 5, "-", 4));
}

// checkDUNSNumber (TEXTFIELD theField [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a valid DUNS number.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkDUNSNumber (theField, emptyOK)
{
	if (checkDUNSNumber.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else
	{ 
		var normalizedDUNS = stripCharsInBag(theField.value, DUNSNumberDelimiters);
		if (!isDUNSNumber(normalizedDUNS, false)) 
			return warnInvalid (theField, iDUNSNumber);
		else 
		{
			theField.value = normalizedDUNS;
			return true;
		}
	}
}

// checkGiftCardNumber (TEXTFIELD theField [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a valid GiftCard number.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkGiftCardNumber (theField, hiddenField, emptyOK)
{
	if (checkGiftCardNumber.arguments.length == 2)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else
	{ 
		var normalizedGiftCard = stripCharsInBag(theField.value, GiftCardNumberDelimiters);
		if (!isGiftCardNumber(normalizedGiftCard, false)) 
			return warnInvalid (theField, iGiftCardNumber);
		else 
		{
		    hiddenField.value = normalizedGiftCard;
			theField.value = reformatGiftCardNumber(normalizedGiftCard);
			return true;
		}
	}
}

// checkFreqDinerNumber (TEXTFIELD theField [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a valid FreqDiner number.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkFreqDinerNumber (theField, hiddenField, emptyOK)
{
	if (checkFreqDinerNumber.arguments.length == 2)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else
	{ 
		var normalizedFreqDiner = stripCharsInBag(theField.value, FreqDinerNumberDelimiters);
		if (!isFreqDinerNumber(normalizedFreqDiner, false)) 
			return warnInvalid (theField, iFreqDinerNumber);
		else 
		{
		    hiddenField.value = normalizedFreqDiner;
			theField.value = reformatFreqDinerNumber(normalizedFreqDiner);
			return true;
		}
	}
}

// checkZIPCode (TEXTFIELD theField [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a valid ZIP code.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkZIPCode (theField, emptyOK)
{
	if (checkZIPCode.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else
	{ 
		var normalizedZIP = stripCharsInBag(theField.value, ZIPCodeDelimiters);
		if (!isZIPCode(normalizedZIP, false)) 
			return warnInvalid (theField, iZIPCode);
		else 
		{
			theField.value = reformatZIPCode(normalizedZIP);
			return true;
		}
	}
}

// takes USPhone, a string of 10 digits
// and reformats as (123) 456-789
function reformatUSPhone (USPhone)
{
	return (reformat (USPhone, "(", 3, ") ", 3, "-", 4));
}

// checkUSPhone (TEXTFIELD theField [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a valid US Phone.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkUSPhone (theField, emptyOK)
{
	if (checkUSPhone.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else
	{
		var normalizedPhone = stripCharsInBag(theField.value, phoneNumberDelimiters);
		if (!isUSPhoneNumber(normalizedPhone, false)) 
			return warnInvalid (theField, iUSPhone);
		else 
		{
			theField.value = reformatUSPhone(normalizedPhone);
			return true;
		}
	}
}

// checkInternationalPhone (TEXTFIELD theField [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a valid International Phone.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkInternationalPhone (theField, emptyOK)
{
	if (checkInternationalPhone.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else
	{
		if (!isInternationalPhoneNumber(theField.value, false)) 
			return warnInvalid (theField, iWorldPhone);
		else
			return true;
	}
}

// checkEmail (TEXTFIELD theField [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is a valid Email.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkEmail (theField, emptyOK)
{
	if (checkEmail.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else if (!isEmail(theField.value, false)) 
		return warnInvalid (theField, iEmail);
	else
		return true;
}

// takes SSN, a string of 9 digits
// and reformats as 123-45-6789
function reformatSSN (SSN)
{
	return (reformat (SSN, "", 3, "-", 2, "-", 4));
}

// Check that string theField.value is a valid SSN.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkSSN (theField, emptyOK)
{
	if (checkSSN.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	else
	{
		var normalizedSSN = stripCharsInBag(theField.value, SSNDelimiters);
		if (!isSSN(normalizedSSN, false)) 
			return warnInvalid (theField, iSSN);
		else 
		{
			theField.value = reformatSSN(normalizedSSN)
			return true;
		}
	}
}

// Check that string theField.value is a valid Year.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkYear (theField, emptyOK)
{
	if (checkYear.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	if (!isYear(theField.value, false)) 
		return warnInvalid (theField, iYear);
	else
		return true;
}

// Check that string theField.value is a valid Month.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkMonth (theField, emptyOK)
{
	if (checkMonth.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	if (!isMonth(theField.value, false)) 
		return warnInvalid (theField, iMonth);
	else
		return true;
}

// Check that string theField.value is a valid Day.
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.
function checkDay (theField, emptyOK)
{
	if (checkDay.arguments.length == 1)
		emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value)))
		return true;
	if (!isDay(theField.value, false)) 
		return warnInvalid (theField, iDay);
	else
		return true;
}

// checkDate (yearField, monthField, dayField, STRING labelString [, OKtoOmitDay==false])
//
// Check that yearField.value, monthField.value, and dayField.value 
// form a valid date.
//
// If they don't, labelString (the name of the date, like "Birth Date")
// is displayed to tell the user which date field is invalid.
//
// If it is OK for the day field to be empty, set optional argument
// OKtoOmitDay to true. It defaults to false.
function checkDate (yearField, monthField, dayField, labelString, OKtoOmitDay)
{
	if (checkDate.arguments.length == 4)
		OKtoOmitDay = false;
	if (!isYear(yearField.value))
		return warnInvalid (yearField, iYear);
	if (!isMonth(monthField.value))
		return warnInvalid (monthField, iMonth);
	if ((OKtoOmitDay == true) && isEmpty(dayField.value))
		return true;
	else if (!isDay(dayField.value)) 
		return warnInvalid (dayField, iDay);
	if (isDate (yearField.value, monthField.value, dayField.value))
		return true;
	alert (iDatePrefix + labelString + iDateSuffix);
	return false;
}

// Validate credit card info.
function checkCreditCard (radio, theField)
{
	var cardType = getRadioButtonValue (radio);
	var normalizedCCN = stripCharsInBag(theField.value, creditCardDelimiters);
	if (!isCardMatch(cardType, normalizedCCN)) 
		return warnInvalid (theField, iCreditCardPrefix + cardType + iCreditCardSuffix);
	else 
	{
		theField.value = normalizedCCN;
		return true;
	}
}

/*	================================================================
	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--;
	}
	if ((sum % 10) == 0)
		return true;
	else
		return false;
}

/*	================================================================
	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;
}

/*	================================================================
	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;
}

/*	================================================================
	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;
}

/*	================================================================
	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;
}

/*	================================================================
	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;
}

/*	================================================================
	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;
}

/*	================================================================
	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;
}

function trim(str)
{ 
	return str.replace(/^\s*([^\s]*)\s*$/, "$1");
}