function ShowHelp(pageinfo)
{
	url = "ShowHelp.php?pageinfo=" + pageinfo;
//	alert(url);
	window.open("http://chemistry.lsu.edu/New/" + url, 'Help','status=no,scrollbars=yes,width=450,height=250');
}


function ChangeSizeToResolution()
{
	for (var i=0; i<document.forms.length; i++)
	{
		for (var j=0; j<document.forms[i].elements.length; j++)
		{
			if (screen.height == 600 && screen.width == 800)
			{
				if (document.forms[i].elements[j].type == "text")
					document.forms[i].elements[j].size = "10";
			}
		}
	}
}



function ShowDays(nday,nmonth,nyear, mform)
{
	//alert("TeST");
	var nDays,month;
//	var day=document.forms[0][nday];
	var day = mform[nday];
	if(day==null)
		return;
//	var months=document.forms[0][nmonth];
//	var years=document.forms[0][nyear];
	var months = mform[nmonth];
	var years = mform[nyear];
		
	month=months[months.selectedIndex].value-1;
	year=years[years.selectedIndex].value;
	if(month == 0 || month == 2 ||month == 4 ||month == 6 || month == 7 || month == 9 || month == 11 ) //Months Having 31 days 0-11
		 nDays=31;
	else if(month == 3 ||month == 5 || month == 8 ||month == 10)
	 	nDays=30; //Months having 30 Days
	else if((month == 1) && (year%4 == 0)) //Feb at a leap year
		nDays=29;
	else
		nDays=28;
	//alert(nDays);
	for(i=0;i<31;i++)
	{
		if(i>nDays-1)
		{
			//alert("day="+day.options[i].value);
			day.options[nDays]=null;
			//alert(i);
			//j++;
			continue;
		}	
		day.options[i]=new Option(i+1,i+1);
	}
}


// Check that the number of characters in a string is between a max and a min
function isValidLength(string, min, max) {

	if (string.length < min || string.length > max) return false;
	else return true;
}

// Check that a credit card number is valid based using the LUHN formula (mod10 is 0)
function isValidCreditCard(number) {
	number = '' + number;
	
	if (number.length > 16 || number.length < 13 ) return false;
	else if (getMod10(number) != 0) return false;
	else if (arguments[1]) {
		var type = arguments[1];
		var first2digits = number.substring(0, 2);
		var first4digits = number.substring(0, 4);
		
		if (type.toLowerCase() == 'visa' && number.substring(0, 1) == 4 &&
			(number.length == 16 || number.length == 13 )) return true;
		else if (type.toLowerCase() == 'mastercard' && number.length == 16 &&
			(first2digits == '51' || first2digits == '52' || first2digits == '53' || first2digits == '54' || first2digits == '55')) return true;
		else if (type.toLowerCase() == 'american express' && number.length == 15 && 
			(first2digits == '34' || first2digits == '37')) return true;
		else if (type.toLowerCase() == 'diners club' && number.length == 14 && 
			(first2digits == '30' || first2digits == '36' || first2digits == '38')) return true;
		else if (type.toLowerCase() == 'discover' && number.length == 16 && first4digits == '6011') return true;
		else if (type.toLowerCase() == 'enroute' && number.length == 15 && 
			(first4digits == '2014' || first4digits == '2149')) return true;
		else if (type.toLowerCase() == 'jcb' && number.length == 16 &&
			(first4digits == '3088' || first4digits == '3096' || first4digits == '3112' || first4digits == '3158' || first4digits == '3337' || first4digits == '3528')) return true;
		
    // if the above card types are all the ones that the site accepts, change the line below to 'else return false'
    else return true;
	}
	else return true;
}

// Check that an email address is valid based on RFC 821
function isValidEmail(address) {
	if (address.indexOf('@') < 3) return false;
	var name = address.substring(0, address.indexOf('@'));
	var domain = address.substring(address.indexOf('@') + 1);
	if (name.indexOf('(') != -1 || name.indexOf(')') != -1 || name.indexOf('<') != -1 || name.indexOf('>') != -1 || name.indexOf(',') != -1 || name.indexOf(';') != -1 || name.indexOf(':') != -1 || name.indexOf('\\') != -1 || name.indexOf('"') != -1 || name.indexOf('[') != -1 || name.indexOf(']') != -1 || name.indexOf(' ') != -1) return false;
	if (domain.indexOf('(') != -1 || domain.indexOf(')') != -1 || domain.indexOf('<') != -1 || domain.indexOf('>') != -1 || domain.indexOf(',') != -1 || domain.indexOf(';') != -1 || domain.indexOf(':') != -1 || domain.indexOf('\\') != -1 || domain.indexOf('"') != -1 || domain.indexOf('[') != -1 || domain.indexOf(']') != -1 || domain.indexOf(' ') != -1) return false;
	return true;
}


// Check that an email address has the form something@something.something
// This is a stricter standard than RFC 821  which allows addresses like postmaster@localhost
function isValidEmailStrict(address) {
	if (isValidEmail(address) == false) return false;
	var domain = address.substring(address.indexOf('@') + 1);
	if (domain.indexOf('.') == -1) return false;
	if (domain.indexOf('.') == 0 || domain.indexOf('.') == domain.length - 1) return false;
	return true;
}


// Check that a US zip code is valid
function isValidZipcode(zipcode) {
	zipcode = removeSpaces(zipcode);
	if (!(zipcode.length == 5) || !isNumeric(zipcode)) return false;
	return true;
}


// Check that a Canadian postal code is valid
function isValidPostalcode(postalcode) {
	if (postalcode.search) {
		postalcode = removeSpaces(postalcode);
		if (postalcode.length == 6 && postalcode.search(/^\w\d\w\d\w\d$/) != -1) return true;
		else if (postalcode.length == 7 && postalcode.search(/^\w\d\w\-d\w\d$/) != -1) return true;
		else return false;
	}
	return true;
}

// Check that a string contains only letters and numbers
function isAlphanumeric(string, ignoreWhiteSpace) {
	if (string.search) {
		if ((ignoreWhiteSpace && string.search(/[^\w\s]/) != -1) || (!ignoreWhiteSpace && string.search(/\W/) != -1)) return false;
	}
	return true;
}

// Check that a string contains only letters
function isAlphabetic(string, ignoreWhiteSpace) {
	if (string.search) {
		if ((ignoreWhiteSpace && string.search(/[^a-zA-Z\s]/) != -1) || (!ignoreWhiteSpace && string.search(/[^a-zA-Z]/) != -1)) return false;
	}
	return true;
}

// Check that a string contains only numbers
function isNumeric(string, ignoreWhiteSpace) {

	if (string.search) {
		if ((ignoreWhiteSpace && string.search(/[^\d\s]/) != -1) || (!ignoreWhiteSpace && string.search(/\D/) != -1)) return false;
	}
	return true;
}

// Remove characters that might cause security problems from a string 
function removeBadCharacters(string) {
	if (string.replace) {
		string.replace(/[<>\"\'%;\)\(&\+]/, '');
	}
	return string;
}

// Remove all spaces from a string
function removeSpaces(string) {
	var newString = '';
	for (var i = 0; i < string.length; i++) {
		if (string.charAt(i) != ' ') newString += string.charAt(i);
	}
	return newString;
}

// Remove leading and trailing whitespace from a string
function trimWhitespace(string) {
	var newString  = '';
	var substring  = '';
	beginningFound = false;
	
	// copy characters over to a new string
	// retain whitespace characters if they are between other characters
	for (var i = 0; i < string.length; i++) {
		
		// copy non-whitespace characters
		if (string.charAt(i) != ' ' && string.charCodeAt(i) != 9) {
			
			// if the temporary string contains some whitespace characters, copy them first
			if (substring != '') {
				newString += substring;
				substring = '';
			}
			newString += string.charAt(i);
			if (beginningFound == false) beginningFound = true;
		}
		
		// hold whitespace characters in a temporary string if they follow a non-whitespace character
		else if (beginningFound == true) substring += string.charAt(i);
	}
	return newString;
}

// Returns a checksum digit for a number using mod 10
function getMod10(number) {
	
	// convert number to a string and check that it contains only digits
	// return -1 for illegal input
	number = '' + number;
	number = removeSpaces(number);
	if (!isNumeric(number)) return -1;
	
	// calculate checksum using mod10
	var checksum = 0;
	for (var i = number.length - 1; i >= 0; i--) {
		var isOdd = ((number.length - i) % 2 != 0) ? true : false;
		digit = number.charAt(i);
		
		if (isOdd) checksum += parseInt(digit);
		else {
			var evenDigit = parseInt(digit) * 2;
			if (evenDigit >= 10) checksum += 1 + (evenDigit - 10);
			else checksum += evenDigit;
		}
	}
	return (checksum % 10);
}