function checkForZero(field) {
	if (field.value == 0 || field.value.length == 0) {
		alert ("This field can't be 0!");
	field.focus(); }
	else
		calculatePayment(field.form);
	}

	function cmdCalc_Click(form) {
		if (form.loan_amount.value == 0 || form.loan_amount.value.length == 0) {
			alert ("The Loan Amount field can't be 0!");
		form.loan_amount.focus(); }
		else if (form.interest_rate.value == 0 || form.interest_rate.value.length == 0) {
			alert ("The Interest Rate field can't be 0!");
		form.interest_rate.focus(); }
		else if (form.loan_term.value == 0 || form.loan_term.value.length == 0) {
			alert ("The Loan Term field can't be 0!");
		form.loan_term.focus(); }
		else
			calculatePayment(form);
		}

		function calculatePayment(form) {
			princ = form.loan_amount.value - form.initial_deposit.value;
			intRate = (form.interest_rate.value/100) / 12;
			months = form.loan_term.value * 12;
			form.monthly_payment.value = Math.floor((princ*intRate)/(1-Math.pow(1+intRate,(-1*months)))*100)/100;
			// form.principle.value = princ;
			// form.number_payments.value = months;
			
		}