//////////////////////////////////////////////////////////////////////////////////////
function formatCurrency(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 trim(stringToTrim) {
	return stringToTrim.replace(/^\s+|\s+$/g,"");
}

function calculate_loan()
{
	var trade = trim(document.loan.tradein.value);
	var downPmt = trim(document.loan.downpay.value);
	if (downPmt == ""){
		downPmt = 0;
	}
	if (trade == ""){
		trade = 0;
	}
	var a = parseFloat(downPmt) + parseFloat(trade);
	var t = document.loan.tax.value;
	var b = document.loan.loanselling.value;
	var b3 = document.loan.loanmonths.value;
	var b4 = document.loan.loaninterest.value;
	//alert(a);
	//alert(b);
	b4 = b4 / 100;
	 t = t / 100;
	if (parseFloat(a)>parseFloat(b)){alert("Down Payment should not be greater than Selling Price");document.loan.downpay.focus();return false;}
	var c = parseInt(parseFloat(b) - parseFloat(a));
	c = (t*b) + c
	document.loan.loanamount.value = c;
     
	//b4 = parseInt(b4) / 100;
	var b10 = c;
	var upper = b10 * ( b4 / 12);
	if(upper==0)  {
		document.loan.loanpayment.value=c/b3;
   		document.loan.loantotal.value=upper;
  	}
  	else {
 		var lower = 1 - ( 1 / Math.pow ( (1+ (b4 / 12)),b3) );
 		var monthly_payment = upper / lower + " ";
 		document.loan.loanpayment.value = formatCurrency(monthly_payment.substring(0,monthly_payment.indexOf('.')) + monthly_payment.substring(monthly_payment.indexOf('.'),monthly_payment.indexOf('.')+3)) ;
 		interestamount = (monthly_payment*b3) - (b - a);
 		interestamount = interestamount + " ";
 		document.loan.loantotal.value =  formatCurrency(interestamount.substring(0,interestamount.indexOf('.')) + interestamount.substring(interestamount.indexOf('.'),interestamount.indexOf('.')+3)) ;
	}
	return false;
}