// detect browser and flag browser type as local variables
var agt=navigator.userAgent.toLowerCase();
var is_major = parseInt(navigator.appVersion);
var is_nav   = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
               && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
               && (agt.indexOf('webtv')==-1));
var is_ie   = (agt.indexOf("msie") != -1);
var is_nav4up = (is_nav && (is_major >= 4));
var is_ie4up  = (is_ie  && (is_major >= 4));

// returns the system date from the client's PC in mm/dd/yyyy format
function getClientSysDate()
{
	var now = new Date();
	var month = now.getMonth();
	var date = now.getDate();
	var year = now.getYear();
	var today;
	
	// format the month field correctly
	if (month == 0) month = '01';
	else if (month == 1) month = '02';
	else if (month == 2) month = '03';
	else if (month == 3) month = '04';
	else if (month == 4) month = '05';
	else if (month == 5) month = '06';
	else if (month == 6) month = '07';
	else if (month == 7) month = '08';
	else if (month == 8) month = '09';
	else if (month == 9) month = '10';
	else if (month == 10) month = '11';
	else if (month == 11) month = '12';
	
	// format the day field correctly (precede single digit days with a zero)
	if (date < 10) date = '0' + date;
	
	// format the year field correctly (IE uses 2 digit years until y2k; NN uses # of years since 1900)
	// IE
	if (is_ie)
	{
		var i = '' + year;
		if (i.length == 2)
		{
			year = '19' + year;
		}
	}
	// Netscape
	if (is_nav)
	{
		year = 1900 + year;
	}
	
	// piece the date together in its correct format
	today = month + '/' + date + '/' + year;

	return(today);
}

function isValidDate(dateString)
{
	var err=0
	var psj=0;
	if (dateString.length != 10) return false;
	b = dateString.substring(0, 2)  // month
	c = dateString.substring(2, 3)  // '/'
	d = dateString.substring(3, 5)  // day
	e = dateString.substring(5, 6)  // '/'
	f = dateString.substring(6, 10) // year
	
	//basic error checking
	if (b<1 || b>12) return false;
	if (c != '/') return false;
	if (d<1 || d>31) return false;
	if (e != '/') return false;
	if (!isValidWholeNumber(f)) return false;
		
	//advanced error checking
	
	// months with 30 days
	if (b==4 || b==6 || b==9 || b==11)
	{
		if (d==31) return false;
	}
	
	// february, leap year
	if (b==2)
	{
		var g=parseInt(f/4);
		if (isNaN(g)) return false;
		if (d>29) return false;
		if (d==29 && ((f/4)!=parseInt(f/4))) return false;
	}
	return true;
}

function isValidEmailAddress(emailString)
{
	if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(emailString))
		return true;
	else
		return false;
}

// check for a null string or a string containing all spaces
function isEmptyString(string)
{
	re=/\S/  // regular expression matches all non-digits
	if (!re.test(string))
		return true;
	else
		return false;
}

// determine if the string contains only numbers
function isValidWholeNumber(inputstring)
{
	if (isEmptyString(inputstring))
		return false;
	re=/\D/  // regular expression matches all non-digits
	if (!re.test(inputstring))
		return true;
	else
		return false;
}

// returns true if the date passed is in the future
function isFutureDate(dateString)
{
	if (Date.parse(dateString) > Date.parse(getClientSysDate()))
		return true;
	else
		return false;
}

// returns true if the date passed is in the past
function isPastDate(dateString)
{
	if (Date.parse(dateString) < Date.parse(getClientSysDate()))
		return true;
	else
		return false;
}

// returns true if the 'from' date preceeds the 'to' date
function isValidDateRange(fromDateString, toDateString)
{
	if (Date.parse(fromDateString) <= Date.parse(toDateString))
		return true;
	else
		return false;
}

// Canadian zip following format: A9A 9A9 or A9A9A9
// ds - There's definitely room for improvment here. This validation
// could be greatly simplified with a regular expression
function isValidCanadianPostalCode(checkzip)
{
    if (checkzip.length == 7)
    {
	    if (checkzip.charAt(3) != " ")
	    {
	        return false;
	    }
	    if ((checkzip.charAt(0) == "0") || (parseFloat(checkzip.charAt(0)) > 0 ))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(1) != "0") && (parseFloat(checkzip.charAt(1)) < 1))
	    {
	        return false;
	    }
	    if (isNaN(parseFloat(checkzip.charAt(1))))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(2) == "0") || (parseFloat(checkzip.charAt(2)) > 0 ))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(4) != "0") && (parseFloat(checkzip.charAt(4)) < 1))
	    {
	        return false;
	    }
	    if (isNaN(parseFloat(checkzip.charAt(4))))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(5) == "0") || (parseFloat(checkzip.charAt(5)) > 0 ))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(6) != "0") && (parseFloat(checkzip.charAt(6)) < 1))
	    {
	        return false;
	    }
	    if (isNaN(parseFloat(checkzip.charAt(6))))
	    {
	        return false;
	    }
	    return true;
	}
    else if (checkzip.length == 6)
    {
	    if ((checkzip.charAt(0) == "0") || (parseFloat(checkzip.charAt(0)) > 0 ))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(1) != "0") && (parseFloat(checkzip.charAt(1)) < 1))
	    {
	        return false;
	    }
	    if (isNaN(parseFloat(checkzip.charAt(1))))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(2) == "0") || (parseFloat(checkzip.charAt(2)) > 0 ))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(3) != "0") && (parseFloat(checkzip.charAt(3)) < 1))
	    {
	        return false;
	    }
	    if (isNaN(parseFloat(checkzip.charAt(3))))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(4) == "0") || (parseFloat(checkzip.charAt(4)) > 0 ))
	    {
	        return false;
	    }
	    if ((checkzip.charAt(5) != "0") && (parseFloat(checkzip.charAt(5)) < 1))
	    {
	        return false;
	    }
	    if (isNaN(parseFloat(checkzip.charAt(5))))
	    {
	        return false;
	    }
	    return true;
	}
	else return false;	
}

function isValidUSPostalCode(checkzip)
{
    if ((!isValidWholeNumber(checkzip)) || (checkzip.length != 5))
    {
        return false;
    }
    return true;
}

// This function populates a select list based on the value of another select
// list. For an example of usage, see the Supplier Registration or Supplier
// Update Profile form.
function fillSelectFromArray(selectCtrl, itemArray, goodPrompt, badPrompt, defaultItem)
{
	var i, j;
	var prompt;
	// empty existing items
	for (i = selectCtrl.options.length; i >= 0; i--)
	{
		selectCtrl.options[i] = null; 
	}
	prompt = (itemArray != null) ? goodPrompt : badPrompt;
	if (prompt == null)
	{
		j = 0;
	}
	else
	{
		selectCtrl.options[0] = new Option(prompt);
		j = 1;
	}
	if (itemArray != null)
	{
		// add new items
		for (i = 0; i < itemArray.length; i++)
		{
			selectCtrl.options[j] = new Option(itemArray[i][0]);
			if (itemArray[i][1] != null)
			{
				selectCtrl.options[j].value = itemArray[i][1]; 
			}
			j++;
		}
		// select first item (prompt) for sub list
		selectCtrl.options[0].selected = true;
	}
}