function checkForZero(field) {
  if (field.value == 0 || field.value.length == 0) {
    alert ("This field cannot have a value of 0. Please adjust this field.");
    field.focus(); }
}

function ChangeText(objname, newtext) {
	obj=document.getElementById(objname);
	if(document.all){		// IE
	     obj.innerText = newtext; } 
	else{					// FF
	    obj.textContent = newtext; }
}


function validNumsDec(refVal) {
	if (refVal.value.length == 0) { return true; }
	var decm = false;	var bDec = true; var bValid = true;
	for (var i=0; i < refVal.value.length; i++) {
		var c = refVal.value.charCodeAt(i);
        if ((c > 57 || c < 48)) {
			if (c==46) {
				if (decm == true) {
					var bDec = false; }
				else {
					decm = true; } }
			else if (c==44 || c==36 || c==37) { }
			else {
				bValid = false; }
			}
	}
	if (bValid==false || bDec==false) {
		alert('You can only enter numbers, commas and one decimal into this field.');
		refVal.focus();	refVal.select(); return false; }
	else { return true; } }

function calculatePayment(form) {
  princ = form.price.value - form.dp.value;
  intRate = form.ir.value / 100;
  CANintRate = Math.pow((1 + intRate / 2),(2 / 12)) - 1;  
  USintRate = intRate / 12;
  months = form.term.value * 12;
  ChangeText('CANpmt','$' + addzeros(Math.floor((princ * CANintRate) / ( 1 - Math.pow( 1 + CANintRate, (-1 * months ))) * 100) / 100));
  ChangeText('USpmt','$' + addzeros(Math.floor((princ * USintRate) / ( 1 - Math.pow( 1 + USintRate , (-1 * months ))) * 100) / 100));
  ChangeText('CANprincipal','$' + addzeros(princ));
  ChangeText('USprincipal','$' + addzeros(princ));
  ChangeText('CANpayment',months);
  ChangeText('USpayment',months);
}

function addzeros(num) {  
	if (num == null) { return 0; }
	if (isNaN(num)) { return 0; }
	if (Number(num) == 0) { return 0; }
	num = parseFloat(num);
	num = Math.round(100*num);
	num = num.toString();
	var p1 = num.substring(0, num.length - 2);
	var p2 = num.substring(num.length - 2, num.length);
	num = p1 + '.' + p2;
	var txtNumber = '' + num;
	var rxSplit = new RegExp('([0-9])([0-9][0-9][0-9][,.])');
	var arrNumber = txtNumber.split('.');
	arrNumber[0] += '.';
	do {
	arrNumber[0] = arrNumber[0].replace(rxSplit, '$1,$2');
	} while (rxSplit.test(arrNumber[0]));
	if (arrNumber.length > 1) {
	return arrNumber.join('');}
	else {
	return arrNumber[0].split('.')[0]; }	
}