function formatCurrency(num) 
{
	if (num) {
		num = num.toString().replace(/\$|,/g,'');
		if(isNaN(num))
			num = "0";
		sign = (num == (num = Math.abs(num)));
		num = Math.floor(num*100+0.50000000001);
		cents = num%100;
		num = Math.floor(num/100).toString();
		if(cents<10)
			cents = "0" + cents;
		for (var i = 0; i < Math.floor((num.length-(1+i))/3); i++)
		num = num.substring(0,num.length-(4*i+3))+','+
		num.substring(num.length-(4*i+3));
		return (((sign)?'':'-') + num + '.' + cents);
	}
}

function calculate_payment(PV, IR, NP) {
  var PMT = (PV * IR) / (1 - Math.pow(1 + IR, -NP));
  return round_decimals(PMT, 2);
}

function round_decimals(original_number, decimals) {
  var result1 = original_number * Math.pow(10, decimals);
  var result2 = Math.round(result1);
  var result3 = result2 / Math.pow(10, decimals);
  return (result3);
}

function run_calculator() {

var present_value = document.loancalc.present_value.value;
var loan_term = document.loancalc.loan_term.value / 12;
var interest_rate = document.loancalc.interest_rate.value;
var balloon_value = document.loancalc.balloon_value.value;

//clean the variables
present_value = present_value.replace(/[\s,\$]/g,"");
interest_rate = interest_rate.replace(/%/,"");
balloon_value = balloon_value.replace(/[\s,\$]/g,"");

interest_rate = document.loancalc.interest_rate.value / 100;

var monthly_payment_balloon = calculate_payment(present_value - balloon_value, interest_rate / 12, loan_term * 12) + (balloon_value * 0.075/12);

if(isNaN(monthly_payment_balloon)) { 
document.loancalc.result.value = monthly_payment_balloon = "Error"; 
} 
else {
document.loancalc.result.value = '$' + formatCurrency(monthly_payment_balloon) ;
}
}

function run_calculator2() {


var present_value = document.calc.present_value.value;
var loan_term = document.calc.loan_term.value / 12;
var interest_rate = document.calc.interest_rate.value / 100;
var balloon_value = document.calc.balloon_value.value;

//clean the variables
present_value = present_value.replace(/[\s,\$]/g,"");

balloon_value = balloon_value.replace(/[\s,\$]/g,"");

var monthly_payment_balloon = calculate_payment(present_value - balloon_value, interest_rate / 12, loan_term * 12) + (balloon_value * 0.075/12);

if(isNaN(monthly_payment_balloon)) { 
document.calc.result.value = monthly_payment_balloon = "Error"; 
} 
else {
document.calc.result.value = formatCurrency(monthly_payment_balloon) ;
}
}