<!--

function calcDownPayment()
{
	var f = document.calculator;
	var price = stripNumber(f.property_value.value);
	var percent = stripNumber(f.percentage_down.value) / 100;

	f.down_payment.value = formatNumber(price * percent);
}

function calcMonthlyPayment()
{
	var f = document.calculator;

	var price = stripNumber(f.property_value.value);		// get price
	var down_payment = stripNumber(f.down_payment.value);	// get down payment

	// get interest rate and loan term - pre-populate if empty
	var interest_rate = (isNaN(stripNumber(f.interest_rate.value)) || f.interest_rate.value == "") ? 8.25 : stripNumber(f.interest_rate.value)
	var loan_term = (isNaN(stripNumber(f.loan_term.value)) || f.loan_term.value == "")  ? 30 : stripNumber(f.loan_term.value)

	var principle = price - down_payment;				// calc principle
	var m_interest_rate = (interest_rate / 100) / 12;	// calc monthly interest rate
	var	m_loan_term = loan_term * 12;					// calc monthly loan term

	/* calculate payment */
	var monthly_payment = Math.floor((principle * m_interest_rate)/(1 - Math.pow((1 + m_interest_rate),(-1 * m_loan_term))) * 100) / 100;

	// populate fields
	f.property_value.value = formatNumber(price);
	f.down_payment.value = formatNumber(down_payment);
	f.interest_rate.value = interest_rate;
	f.loan_term.value = loan_term;
	f.montly_mortgage_costs.value = formatNumber(monthly_payment);

	if (f.total_loan_amount) f.total_loan_amount.value = formatNumber(principle);
	if (f.total_amount_repaid) f.total_amount_repaid.value = formatNumber(monthly_payment * m_loan_term);
}


function stripNumber(val)
{
	val = val.replace(/[^0123456789.]/g, "");
	val = Number(val);

	return val;
}

function formatNumber(val)
{
	val = (val).toLocaleString();
	return val;
}

//-->