/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/*Calculator HTML*/
function getCal()
{
var imagePath= 'http://www.nowcreditcards.co.uk/creditcal/images';
document.write('');
document.write('');
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/*Calculator JavaScript*/
var intRate;
var mnthRepay;
var monthsClearDebt;
var yearsClearDebt;
// round a number to X decimals
function round(number, plcs)
{
plcs = (!plcs ? 2 : plcs);
return Math.round(number * Math.pow(10, plcs)) / Math.pow(10, plcs);
}
// get the values from the Repay table into JS variables
function getValsRepay()
{
crdBalance = new Number(document.frmCard.crdBalanceRepay.value);
intRate = new Number(document.frmCard.intRateRepay.value);
mnthRepay = new Number(document.frmCard.mnthRepay.value);
}
// get the values from the Clear your debt table into JS variables
function getValsMonths()
{
crdBalance = new Number(document.frmCard.crdBalanceMonths.value);
intRate = new Number(document.frmCard.intRateMonths.value);
monthsClearDebt = document.frmCard.monthsSelect[document.frmCard.monthsSelect.selectedIndex].value;
yearsClearDebt = document.frmCard.yearsSelect[document.frmCard.yearsSelect.selectedIndex].value;
}
// check if a given variable is a valid number. isNAN tests if a variable is Not A Number
function isValidNum(num)
{
var isValidNum = false;
if ( !isNaN(num) && num != "" && num != undefined){
isValidNum = true;
}
return isValidNum;
}
// does all the work
function CalcResultsRepay(clickCalc)
{
var remainingBalance = 0;
var mnIntRate = null;
var monthsPaid = 0;
var monthlyIntPay = null;
var totIntPaid = 0;
var paidOff = true; // can the card be paid off based on the repayment and interest amounts
var yearsStr = 'years';
var monthsStr = 'months';
// calc the monthly interest rate
mnIntRate = GetMnthIntRate();
// simulate making payments each month
remainingBalance = crdBalance;
while (remainingBalance > 0)
{
monthsPaid++;
// calc monthly int payment
monthlyIntPay = remainingBalance * mnIntRate;
// add int payment and subtract payment from remaining balance
remainingBalance = remainingBalance + monthlyIntPay - mnthRepay;
// keep runnning total of interested paid
totIntPaid = totIntPaid + monthlyIntPay;
// is the base amount going up instead of down because of interest
if (remainingBalance >= crdBalance)
{
paidOff = false;
if (clickCalc)
{
alert('Your monthly payment is less than your monthly interest fee');
}
break;
}
}
// if the card was able to be paid off, update the result boxes
if (!paidOff)
{
ResetFieldsRepay();
}
else
{
if (monthsPaid >= 12)
{
var years = Math.floor(monthsPaid/12);
var months = monthsPaid-(years*12);
if(years==1){
yearsStr = 'year';
}
if(months==1){
monthsStr = 'month';
}
document.frmCard.resultRepay.value = years+' '+yearsStr+', '+months+' '+monthsStr;
}
else
{
if(monthsPaid==1){
monthsStr = 'month';
}
document.frmCard.resultRepay.value = monthsPaid+' '+monthsStr;
}
// total cost -> document.frmCard.resultBox2.value = (crdBalance+totIntPaid).toFixed(2);
}
}
// calc the monthly interest rate
function GetMnthIntRate()
{
return (parseFloat(intRate)/100)/12;
}
function CalcResultsMonths ()
{
// want card paid off in X months, work out required monthly payment and total cost
var mnIntRate = null;
// calc the monthly interest rate
mnIntRate = GetMnthIntRate();
var totalMonths = ((parseInt(yearsClearDebt)*12) + parseInt(monthsClearDebt));
var mnthlyIntCost = (crdBalance*mnIntRate);
var change = 1-Math.pow((1+mnIntRate),-totalMonths);
var reqPayment = (mnthlyIntCost / change).toFixed(2);
document.frmCard.resultMonths.value = reqPayment;
// total cost -> document.frmCard.resultBox2.value = (reqPayment*totalMonths).toFixed(2);
}
function ResetFieldsRepay()
{
document.frmCard.resultRepay.value = '';
}
function ResetFieldsMonths()
{
document.frmCard.resultMonths.value = '';
}
function UpdateRepay()
{
// get the forms variables
getValsRepay();
if (!isValidNum(crdBalance))
{
alert('Please enter a valid card balance');
document.frmCard.crdBalanceRepay.focus();
}
else if (!isValidNum(intRate))
{
alert('Please enter a valid interest rate');
document.frmCard.intRateRepay.focus();
}
else if (!isValidNum(mnthRepay))
{
alert('Please enter a valid monthly repayment');
document.frmCard.mnthRepay.focus();
}
else
{
CalcResultsRepay(true);
}
}
function UpdateMonths()
{
// get the forms variables
getValsMonths();
if (!isValidNum(crdBalance))
{
alert('Please enter a valid card balance');
document.frmCard.crdBalanceMonths.focus();
}
else if (!isValidNum(intRate))
{
alert('Please enter a valid interest rate');
document.frmCard.intRateMonths.focus();
}
else if (monthsClearDebt == 0 && yearsClearDebt == 0)
{
alert('Please select your desired time frame');
document.frmCard.yearsSelect.focus();
}
else
{
CalcResultsMonths(true);
}
}
// auto populate the 2nd card balance box
function PopCardBalRepay()
{
if (document.frmCard.crdBalanceMonths.value == null || document.frmCard.crdBalanceMonths.value == ''){
document.frmCard.crdBalanceMonths.value = document.frmCard.crdBalanceRepay.value;
}
}
// auto populate the 2nd card balance box
function PopCardBalMonths()
{
if (document.frmCard.crdBalanceRepay.value == null || document.frmCard.crdBalanceRepay.value == ''){
document.frmCard.crdBalanceRepay.value = document.frmCard.crdBalanceMonths.value;
}
}