function jumpBox(list)
	{
	   location.href = list.options[list.selectedIndex].value
	   }

	function checkNumber(input, min, max, msg)
	{
		msg = msg + " field has invalid data: " + input.value;
		var str = input.value;
		for (var i = 0; i < str.length; i++) {
			var ch = str.substring(i, i + 1)
			if ((ch < "0" || "9" < ch) && ch != '.') {
				alert(msg);
				return false;
			}
		}
		var num = 0 + str
		if (num < min || max < num) {
			alert(msg + " not in range [" + min + ".." + max + "]");
			return false;
		}
		input.value = str;
		return true;
	}


	function computeField(input)
	{
		if (input.value != null && input.value.length != 0)
			input.value = "" + eval(input.value);
		computeForm(input.form);
	}


	function computeForm(form)
	{
		if ((form.payments.value == null || form.payments.value.length == 0) ||
			(form.interest.value == null || form.interest.value.length == 0) ||
			(form.purchase.value == null || form.purchase.value.length == 0)) {
			return;
		}
		if (!checkNumber(form.payments, 1, 480, "Loan Period") ||
			!checkNumber(form.interest, .001, 99, "Interest") ||
			!checkNumber(form.purchase, 100, 10000000, "Purchase")) {
			form.payment.value = "Invalid";
			return;
		}
		var principal  = (form.purchase.value - form.deposit.value);	
		form.payment.value  = Math.round(payment(principal, form.interest.value, form.payments.value, 26));	
		form.mindep.value  = (form.purchase.value * .05);	
	}

	function payment(loanAmount, intRate, period, paymentsPerYear)
	{
		var rate = intRate / (100 * paymentsPerYear);
		var payments = period * paymentsPerYear;
		return loanAmount * rate / (1 - Math.pow(1 + rate, - payments));
	}