function floor(number) {
	return Math.floor(number*Math.pow(10,2))/Math.pow(10,2);
}

function calculate() {
	var MonthlyInterest = document.getElementById("InterestRate").value / 1200;
	var base = 1;
	var mBase = 1 + MonthlyInterest;
	var LoanYears = document.getElementById("LoanYears").value;
	var InterestRate = document.getElementById("InterestRate").value;
	var LoanAmount = document.getElementById("LoanAmount").value;
	var AnnualTax = document.getElementById("AnnualTax").value;
	var AnnualInsurance = document.getElementById("AnnualInsurance").value;
	
	for (var i = 0; i < LoanYears * 12; i++) {
    	base = base * mBase;
	}
	
	document.getElementById("Principle").value = FormatCurrency(floor(LoanAmount * MonthlyInterest / (1 - (1 / base))));
  	document.getElementById("MonthlyTax").value = FormatCurrency(floor(AnnualTax / 12));
  	document.getElementById("MonthlyInsurance").value = FormatCurrency(floor(AnnualInsurance / 12));
	var theSum = LoanAmount * MonthlyInterest / ( 1 - (1/base)) + AnnualTax / 12 + AnnualInsurance / 12;
	document.getElementById("MonthlyPayment").value = FormatCurrency(floor(theSum));
}

function FormatCurrency(amount) {
	var i = parseFloat(amount);
	if(isNaN(i)) { i = 0.00; }

	var minus = '';
	if(i < 0) { minus = '-'; }
	i = Math.abs(i);
	i = parseInt((i + .005) * 100);
	i = i / 100;
	s = new String(i);

	if(s.indexOf('.') < 0) { s += '.00'; }

	if(s.indexOf('.') == (s.length - 2)) { s += '0'; }
	s = minus + s;
	return "$" + s;
}