// FormChekMod1.js

//

// SUMMARY

//

// This is a set of JavaScript functions for validating input on 

// an HTML form.  Functions are provided to validate:

//

//      - U.S. phone/fax numbers

//      - U.S. ZIP codes (5 or 9 digit postal codes)

//      - email addresses

//	     - dates (entry of year, month, and day and validity of combined date)

//	     - credit card numbers

//

// 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 = "."





// non-digit characters which are allowed in phone numbers

var phoneNumberDelimiters = "().- ";





// characters which are allowed in US phone numbers

var validUSPhoneChars = digits + phoneNumberDelimiters;





// U.S. phone numbers have 10 digits.

// They are formatted as 123 456 7890 or (123) 456-7890.

var digitsInUSPhoneNumber = 10;







// non-digit characters which are allowed in ZIP Codes

var ZIPCodeDelimiters = "-";







// our preferred delimiter for reformatting ZIP Codes

var ZIPCodeDelimeter = "-"







// U.S. ZIP codes have 5 or 9 digits.

// They are formatted as 12345 or 12345-6789.

var digitsInZIPCode1 = 5

var digitsInZIPCode2 = 9





// non-digit characters which are allowed in credit card numbers

var creditCardDelimiters = " "





// 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."



// 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 sPhone = "Phone Number"

var sFax = "Fax Number"

var sEmail = "Email"

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 iZIPCode = "This field must be a 5 or 9 digit U.S. ZIP Code (like 91786). Please reenter it now."

var iUSPhone = "This field must be a 10 digit U.S. phone number (like 800 555 1212). Please reenter it now."

var iEmail = "This field must be a valid email address (like info@xyz.com). 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."







// 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 91786)."

var pUSPhone = "10 digit U.S. phone number (like 800 555 1212)."

var pEmail = "valid email address (like info@xyz.com)."

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.



var defaultEmptyOK = true









// Attempting to make this library run on Navigator 2.0,

// so I'm supplying this array creation routine as per

// JavaScript 1.0 documentation.  If you're using 

// Navigator 3.0 or later, you don't need to do this;

// you can use the Array constructor instead.



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;









// 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 = "";



    // 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.

//

// However, because of an apparent bug in indexOf on 

// Navigator 2.0.2, the below loop does not work as the

// body of stripInitialWhitespace:

//

// while ((i < s.length) && (whitespace.indexOf(s.charAt(i)) != -1))

//   i++;

//

// ... so we provide this workaround function charInString

// instead.

//

// charInString (CHARACTER c, STRING s)

//

// Returns true if single character c (actually a string)

// is contained within string s.



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);

}















// 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.



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.





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;

    }



    // All characters are numbers.

    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 -.



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.





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.



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;

}







// isUSPhoneNumber (STRING s [, BOOLEAN emptyOK])



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)

}







// isZIPCode (STRING s [, BOOLEAN emptyOK])



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)))

}







// isEmail (STRING s [, BOOLEAN emptyOK])



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])



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])



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])



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)

{   // catch invalid years (not 2- or 4-digit) and invalid months and days.

    if (! (isYear(year, false) && isMonth(month, false) && isDay(day, false))) return false;



    // 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;

}









/* 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, put focus in it, and return false.



function warnInvalid (theField, s)

{   theField.blur()

    theField.focus()

	 theField.select()

    alert(s)

    theField.blur()

    theField.focus()

	 theField.select()

    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;

}







// 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));

}









// 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 

      {  // if you don't want to insert a hyphen, comment next line out

         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 

       {  // if you don't want to reformat as (123) 456-789, comment next line out

          theField.value = reformatUSPhone(normalizedPhone)

          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;

}









// 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)

{   // 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);

    if (isDate (yearField.value, monthField.value, dayField.value))

       return true;

    alert (iDatePrefix + labelString + iDateSuffix)

    return false

}







// Get checked value from radio button.



function getRadioButtonValue (radio)

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

    {   if (radio[i].checked) { break }

    }

    return radio[i].value

}





function checkMDY(theField,emptyOK){

    if (checkMDY.arguments.length == 1) emptyOK = defaultEmptyOK;

    if (isEmpty(theField.value)) return emptyOK;

    else{

      var dateString = stripCharsInBag(theField.value,"-/ ");

      var mm = dateString.substring(0,2);

      var dd = dateString.substring(2,4);

      var yyyy = dateString.substring(4,theField.value.length);

      if (!isMonth(mm)) return warnInvalid(theField,theField.name + " contains an invalid month. Format must be MM/DD/YYYY.");

      if (!isDay(dd)) return warnInvalid(theField,theField.name + " contains an invalid day. Format must be MM/DD/YYYY.");

      if (!isYear(yyyy)) return warnInvalid(theField,theField.name + " contains an invalid year. Format must be MM/DD/YYYY.");

      else if (yyyy.length == 2) yyyy = (parseInt(yyyy)+2000);

      if (isDate(yyyy.toString(),mm.toString(),dd.toString())){

        theField.value = mm+"/"+dd+"/"+yyyy;

        return true;

      }

      else{

        warnInvalid(theField,theField.name + " contains an invalid date");

        return false;

      }

    }

}