// Taken from FormCheck.js :
//
// 18 Feb 97 created Eric Krock
// (c) 1997 Netscape Communications Corporation

// VARIABLE DECLARATIONS

var digits = "0123456789";

var lowercaseLetters = "abcdefghijklmnopqrstuvwxyz"

var uppercaseLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

// whitespace characters
var whitespace = " \t\n\r";


// decimal point character differs by language and culture
var decimalPointDelimiter = "."


// CONSTANT STRING DECLARATIONS
// (grouped for ease of translation and localization)

// 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."


// i is an abbreviation for "invalid"

var iDay = "This field must be a day number between 1 and 31.  Please reenter it now."
var iMonth = "This field must be a valid month of the form \"mmm\" eg. Jan.	 Please reenter it now."
var iYear = "This field must be a 4 digit year number.	Please reenter it now."
var iName = "This field must be a name of the form First Last.	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 iPostalCode = "This field must contain a valid Canadian postal code (eg. A1B 2C3)."
var iEmail = "This field must be a valid email address (eg. foo@bar.com). Please reenter it now."

var defaultEmptyOK = false


function makeArray(n) {
//*** BUG: If I put this line in, I get two error messages:
//(1) Window.length can't be set by assignment
//(2) daysInMonth has no property indexed by 4
//If I leave it out, the code works fine.
//	 this.length = n;
   for (var i = 1; i <= n; i++) {
	  this[i] = 0
   } 
   return this
}


var daysInMonth = makeArray(12);
daysInMonth[1] = 31;
daysInMonth[2] = 29;   // must programmatically check this
daysInMonth[3] = 31;
daysInMonth[4] = 30;
daysInMonth[5] = 31;
daysInMonth[6] = 30;
daysInMonth[7] = 31;
daysInMonth[8] = 31;
daysInMonth[9] = 30;
daysInMonth[10] = 31;
daysInMonth[11] = 30;
daysInMonth[12] = 31;

var months = new Array(13);
months[1]= "Jan";
months[2]= "Feb";
months[3]= "Mar";
months[4]= "Apr";
months[5]= "May";
months[6]= "Jun";
months[7]= "Jul";
months[8]= "Aug";
months[9]= "Sep";
months[10]= "Oct";
months[11]= "Nov";
months[12]= "Dec";


// 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 = "";

	// Search through string's characters one by one.
	// If character is not in bag, append to returnString.

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

	// Search through string's characters one by one.
	// If character is in bag, append to returnString.

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


// WORKAROUND FUNCTION FOR NAVIGATOR 2.0.2 COMPATIBILITY.
//
// The below function *should* be unnecessary.	In general,
// avoid using it.	Use the standard method indexOf instead.


function charInString (c, s)
{	for (i = 0; i < s.length; i++)
	{	if (s.charAt(i) == c) return true;
	}
	return false
}



// 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) && charInString (s.charAt(i), whitespace))
	   i++;
    
	return s.substring (i, s.length);
}

// Removes trailing whitespace

function stripTrailingWhitespace (s)
{
	var i = s.length-1;

	while ((i > 0) && charInString (s.charAt(i), whitespace))
		i--;

	return s.substring (0, i+1);
}

// 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))
}



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) ) );
}

// isInteger (STRING s [, BOOLEAN emptyOK])
// 
// Returns true if all characters in string s are numbers.
//

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;
}
// 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) ) );
}



// 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.
//
// 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.
//

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;
}


// 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 whitespace?
    if (isWhitespace(s)) 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;
}


// isYear (STRING s [, BOOLEAN emptyOK])
// 
// isYear returns true if string s is a valid 
// Year number.	 Must be 4 digits.

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 == 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));
}

function pcase(str) { 
   strlen = str.length 
   jj = str.substring(0,1).toUpperCase() 
   jj = jj + str.substring(1,strlen).toLowerCase() 
   for (i = 2; i <= strlen; i++) { 
	  if (jj.charAt(i)==" ") { 
		 lefthalf = jj.substring(0,i+1) 
		 righthalf = jj.substring(i+1,strlen) 
		 righthalf = righthalf.substring(0,1).toUpperCase()+righthalf.substring(1,strlen) 
		 jj=lefthalf+righthalf 
	  } 
   } 
   return jj
}

// isMonth (STRING s [, BOOLEAN emptyOK])
// 
// isMonth returns true if string s is a valid 
// month number between jan and dec.

function isMonth (s)
{   
	if (isEmpty(s)) 
	   if (isMonth.arguments.length == 1) return defaultEmptyOK;
	   else return (isMonth.arguments[1] == true);

	var month = pcase(isMonth.arguments[0]);

	for (var i=1;i<13;i++)
		if (month == months[i]) return true;
	return false;
}



// 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);
	var sRealInt = Number(s);
	return isIntegerInRange (sRealInt, 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)
{
	// Explicitly change type to integer to make code work in both
	// JavaScript 1.1 and JavaScript 1.2.
	var intYear = parseInt(year);
	var intMonth = parseInt(month);
	var intDay = parseInt(day);

	// catch invalid days, except for February
	if (intDay > daysInMonth[intMonth]) return false; 

	if ((intMonth == 2) && (intDay > daysInFebruary(intYear))) return false;

	return true;
}

// isPostalCode (STRING pcode)
//
// isPostalCode returns true if string argument
// forms a valid Canadian postal code (eg A1B 2C3).
// 

function isPostalCode (pcode)
{
	if (pcode.length == 6) 
	{
		if (isLetter(pcode.charAt(0)) && isDigit(pcode.charAt(1)) && isLetter(pcode.charAt(2)) &&
				isDigit(pcode.charAt(3)) && isLetter(pcode.charAt(4)) && isDigit(pcode.charAt(5)))
			return true;
	}
	else
		return false;
}


// 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;
}




/* 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)
{	// Next line is needed on NN3 to avoid "undefined is not a number" error
	// in equality comparison below.
	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;
}

// checkPostalCode (TEXTFIELD theField, STRING s, [, BOOLEAN emptyOK==false])
//
// Check that string theField.value is not a valid Canadian postal code (NLN LNL).
//
// For explanation of optional argument emptyOK,
// see comments of function isInteger.

function checkPostalCode (theField, s, emptyOK)
{	// Next line is needed on NN3 to avoid "undefined is not a number" error
	// in equality comparison below.
	if (checkPostalCode.arguments.length == 2) emptyOK = defaultEmptyOK;
	theField.value = stripWhitespace(theField.value.toUpperCase());
	if ((emptyOK == true) && (isEmpty(theField.value))) return true;

	if (!isPostalCode(theField.value))
		return warnInvalid(theField, iPostalCode);
	else
		return true;

}


// checkName (TEXTFIELD theField, STRING s, [, BOOLEAN emptyOK==false])
//
// A Name has to be a valid string and in Proper Case format, and have
// no leading or trailing whitespace

function checkName (theField, s, emptyOK)
{
	if (checkString(theField, s, emptyOK))
	{
		fieldVal = stripInitialWhitespace(theField.value);
		fieldVal = stripTrailingWhitespace(fieldVal);
		fieldVal = pcase(fieldVal);
		theField.value = pcase(fieldVal);
		
		return true;
	}
	else
		return warnInvalid (theField, iName);
}

// Check that string theField.value is nonneg int

function checkNonNegInt (theField, emptyOK)
{	if (checkNonNegInt.arguments.length == 1) emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value))) return true;
	if (!isNonnegativeInteger(theField.value, false)) 
	   return warnInvalid (theField, "This field must contain a number greater than -1.");
	else return true;
}

// Check that string theField.value is nonneg int & of length "fixedLength"

function checkFixedNonNegInt (theField, fixedLength, emptyOK)
{	if (checkFixedNonNegInt.arguments.length == 2) emptyOK = defaultEmptyOK;
	if ((emptyOK == true) && (isEmpty(theField.value))) return true;

	if (theField.value.length == fixedLength) {
		if (!isNonnegativeInteger(theField.value, false)) 
			return warnInvalid (theField, "This field must contain a number greater than -1.");
		else return true;
	}
	else
		return warnInvalid (theField, "This field must contain exactly " + fixedLength + " digits.");
	
}

// 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.
//

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 
	{
		theField.value = pcase(theField.value);
		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)
{	// Next line is needed on NN3 to avoid "undefined is not a number" error
	// in equality comparison below.
	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);

	var intMonth = 0;
	for (var i=1;i<13;i++)
	{
		if (monthField.value == months[i]) 
		{
			intMonth=i;
			break;
		}
	}
	if (isDate (yearField.value, intMonth, dayField.value))
		return true;
	alert (iDatePrefix + labelString + iDateSuffix)
	return false
}


function checkPassword (passwordField)
{
	if (passwordField.value.length < 6) {
		alert ("The password must be at least 6 characters in length.");
		return false;
	}
	if (isAlphabetic(passwordField.value)) {
		alert ("The password must contain at least 1 non-alphabetic character.");
		return false;
	}
	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;
}