function calculateBYOB() {
	var numFamilyMembers 	= document.getElementById('numFamilyMembers').value;
	
	var bagsSaved 			= document.getElementById('bagsSaved');
	var fiveFriends 		= document.getElementById('fiveFriends');
	var fiveYears 			= document.getElementById('fiveYears');

	if (isNaN(numFamilyMembers)) {
	  	bagsSaved.value 	= 'Error';
		fiveFriends.value 	= 'Error';
		fiveYears.value 	= 'Error';
	} 
	else {
	  	var numBagsSaved = Math.round(numFamilyMembers * 250);

		bagsSaved.value 	= numBagsSaved;
		fiveFriends.value 	= numBagsSaved * 5;
		fiveYears.value 	= numBagsSaved * 5 * 5;
	}
	return false;
}

function calculateRetailer() {
	var numCustomers 		= document.getElementById('numCustomers').value;
	var numStores 			= document.getElementById('numStores').value;
	
	var totalAnnual 		= document.getElementById('totalAnnual');
	var tenDollars 			= document.getElementById('tenDollars');
	var tenNumbers 			= document.getElementById('tenNumbers');
	var twentyDollars 		= document.getElementById('twentyDollars');
	var twentyNumbers 		= document.getElementById('twentyNumbers');
	var thirtyDollars 		= document.getElementById('thirtyDollars');
	var thirtyNumbers 		= document.getElementById('thirtyNumbers');
	
	var annualBagsSaved 	= numCustomers * 52 * numStores * 5;
	var annualDollarsSaved 	= annualBagsSaved * 0.02;
	
	totalAnnual.value 	= dollarFormat(annualDollarsSaved);
	tenDollars.value 	= dollarFormat(annualDollarsSaved 	* 0.1);
	tenNumbers.value 	= annualBagsSaved 					* 0.1;
	twentyDollars.value	= dollarFormat(annualDollarsSaved 	* 0.2);
	twentyNumbers.value	= annualBagsSaved 					* 0.2;
	thirtyDollars.value	= dollarFormat(annualDollarsSaved 	* 0.3);
	thirtyNumbers.value	= annualBagsSaved 					* 0.3;
	
	return false;
}

function dollarFormat(num) {
	return '$' + formatNumber(num, 0, ',', '', '', '', '', '')
}

// number formatting function
// copyright Stephen Chapman 24th March 2006
// permission to use this function is granted provided
// that this copyright notice is retained intact

function formatNumber(num,dec,thou,pnt,curr1,curr2,n1,n2) {var x = Math.round(num * Math.pow(10,dec));if (x >= 0) n1=n2='';var y = (''+Math.abs(x)).split('');var z = y.length - dec;y.splice(z, 0, pnt);while (z > 3) {z-=3; y.splice(z,0,thou);}var r = curr1+n1+y.join('')+n2+curr2;return r;}