<!--
document.write('<!-- Hide the script -->');


var LoanAmt;
var Rate;
var Period;
var Payment;

function CalcPayment(form) {
  // This calculates the payment amount from the other three values

  // Assign the values from the form
  LoanAmt = parseFloat(form.LoanAmt.value);
  Rate = parseFloat(form.Rate.value);
  Period = parseInt(form.Period.value);

  // Validate the values that are coming from the form
  if (isNaN(LoanAmt)) {  alert("Missing Loan Amount");   return;  }
  if (isNaN(Rate))    {  alert("Missing Interest Rate"); return;  }
  if (isNaN(Period))  {  alert("Missing Period Value");  return;  }

  // The Rate is the yearly interest rate -- adjust to make a monthly rate.
  //   Also, the rate is a percentage, so divide by 100 to make the usable
  //   amount;
  if (Rate >= 1) { Rate /= 100; }
  Rate /= 12;

  // Calculate the payment based on the other three amounts
  Payment = LoanAmt *
               (Rate * Math.pow(1+Rate, Period)) /
                (Math.pow(1+Rate, Period) - 1);

  // Format the value by multiplying by 100, rounding the number, then
  //   dividing that result to get two decimal places
  Payment = Math.ceil(Payment*100) / 100;
  form.PaymentAmt.value = Payment.toString();

  return;
}

function CalcLoanAmt(form) {
  // This calculates the loan principal amount from the other three values

  // Assign the values from the form
  Rate = parseFloat(form.Rate.value);
  Period = parseInt(form.Period.value);
  Payment = parseFloat(form.PaymentAmt.value);

  // Validate the values that are coming from the form
  if (isNaN(Rate))    {  alert("Missing Interest Rate");   return;  }
  if (isNaN(Period))  {  alert("Missing Period Value");    return;  }
  if (isNaN(Payment)) {  alert("Missing Payment Amount");  return;  }

  // The Rate is the yearly interest rate -- adjust to make a monthly rate.
  //   Also, the rate is a percentage, so divide by 100 to make the usable
  //   amount;
  if (Rate >= 1) { Rate /= 100; }
  Rate /= 12;

  // Calculate the loan amount based on the other three amounts
  LoanAmt = Payment /
               ((Rate * Math.pow(1+Rate, Period)) /
                (Math.pow(1+Rate, Period) - 1));

  // Format the value by multiplying by 100, rounding the number, then
  //   dividing that result to get two decimal places
  form.LoanAmt.value = (Math.floor(LoanAmt*100) / 100).toString();

  return;
}

function CalcPeriod(form) {
  // This calculates the loan principal amount from the other three values

  // Assign the values from the form
  LoanAmt = parseFloat(form.LoanAmt.value);
  Rate = parseFloat(form.Rate.value);
  Payment = parseFloat(form.PaymentAmt.value);

  // Validate the values that are coming from the form
  if (isNaN(LoanAmt)) {  alert("Missing Loan Amount");     return;  }
  if (isNaN(Rate))    {  alert("Missing Interest Rate");   return;  }
  if (isNaN(Payment)) {  alert("Missing Payment Amount");  return;  }

  // The Rate is the yearly interest rate -- adjust to make a monthly rate.
  //   Also, the rate is a percentage, so divide by 100 to make the usable
  //   amount;
  if (Rate >= 1) { Rate /= 100; }
  Rate /= 12;

  // If the payment is too low, the denominator in the first
  //   fraction goes negative, and the natural log of a negative
  //   is NaN.  So, there is a minimum payment -- or, you would
  //   never reduce the principal!
  if (Payment - LoanAmt*Rate < 0) {
    alert("Payment amount too small.\nIt must be at least $" +
          (Math.ceil(LoanAmt*Rate)).toString());

    return;
  }

  // Calculate the period based on the other three amounts
  with (Math) {
    Period = ceil(log(Payment / (Payment - LoanAmt*Rate)) /
                  log(1 + Rate));
  }

  // Format the value by multiplying by 100, rounding the number, then
  //   dividing that result to get two decimal places
  form.Period.value = Period.toString();

  // Re-adjust the payment to reflect this new period
  CalcPayment(form);

  return;
}

function CalcRate(form) {
  // This calculates the interest rate from the other three values.
  //   I could not find a formula for the interest rate, so I
  //   find the value iteratively.
  var TempPayment;
  var Increment;

  // Assign the values from the form
  LoanAmt = parseFloat(form.LoanAmt.value);
  Payment = parseFloat(form.PaymentAmt.value);
  Period  = parseInt(form.Period.value);

  // Validate the values that are coming from the form
  if (isNaN(LoanAmt)) {  alert("Missing Loan Amount");     return;  }
  if (isNaN(Payment)) {  alert("Missing Payment Amount");  return;  }
  if (isNaN(Period))  {  alert("Missing Period Value");    return;  }

  // Remember the payment value as an integer (for comparing)
  TempPayment = -9999;   // Init
  Rate = 50 / 1200;      // Yearly rate of 50% (starting point)
  Increment = Rate/2;

  with (Math) {
    while (abs(Payment - TempPayment) > 0.005 ) {

      // Calculate the payment based on the other three amounts
      TempPayment = LoanAmt *
                    (Rate * pow(1+Rate, Period)) /
                    (pow(1+Rate, Period) - 1);

      if (TempPayment > Payment)      { Rate -= Increment;  }
      else if (TempPayment < Payment) { Rate += Increment;  }

      Increment /= 2;
    }
  }

  // Format the rate
  form.Rate.value = (parseInt(Rate * 1200000) / 1000).toString();

  return;
}

function ValToMoney(Val, ConverMethod) {
  // Format the passed value as a float with two decimal places
  var FmtVal;
  var DecPos;

  // If the conversion method is 1, use the ceil() method to convert
  //   the value and not the round()
  if (ConverMethod == 1) {
    FmtVal = (Math.ceil(Val * 100) / 100).toString();
  }
  else {
    FmtVal = (Math.round(Val * 100) / 100).toString();
  }

  // Make sure it has two decimal places after the decimal point
  DecPos = FmtVal.indexOf('.');
  if (DecPos == -1)                   {  FmtVal += '.00'; }
  else if (DecPos == FmtVal.length-1) {  FmtVal += '00';  }
  else if (DecPos == FmtVal.length-2) {  FmtVal += '0';   }

  return FmtVal;
}

function ShowAmoritazation(form) {
  // Show the amortization table in the 2nd frame
  var Counter;
  var Bal;
  var Interest;
  var Principal;
  var TotInterest;

  // Assign the values from the form
  LoanAmt = parseFloat(form.LoanAmt.value);
  Rate = parseFloat(form.Rate.value);
  Payment = parseFloat(form.PaymentAmt.value);
  Period = parseInt(form.Period.value);

  // Validate the values that are coming from the form
  if (isNaN(LoanAmt)) {  alert("Missing Loan Amount");       return;  }
  if (isNaN(Rate))    {  alert("Missing Interest Rate");     return;  }
  if (isNaN(Payment)) {  alert("Missing Payment Amount");    return;  }
  if (isNaN(Period))  {  alert("Missing Period Amount");     return;  }

  // The Rate is the yearly interest rate -- adjust to make a monthly rate.
  //   Also, the rate is a percentage, so divide by 100 to make the usable
  //   amount;
  if (Rate > 1) { Rate /= 100; }
  Rate /= 12;

  // Write out the schedule on the 2nd frame
  with (parent.frames[1].document) {

    open();
    clear();
    writeln('<HTML><BODY BGCOLOR=#FFFFFF>');

    write('</CENTER>');

    // -------------------------------
    // Show the parameters at the top
    // -------------------------------
    write('<TABLE BORDER=0>');
    write('<TR>');

    write('<TD ALIGN=LEFT>Loan Amount</TD>');
    write('<TD ALIGN=LEFT BGCOLOR=#CACACA>$' + LoanAmt.toString() + '</TD>');

    write('<TD WIDTH=30></TD>');

    write('<TD ALIGN=LEFT>Period</TD>');
    if (Period == 1) {
      write('<TD ALIGN=LEFT BGCOLOR=#CACACA>1 month</TD>');
    }
    else {
      write('<TD ALIGN=LEFT BGCOLOR=#CACACA>' + Period.toString() + ' months</TD>');
    }
    write('</TR>');

    write('<TR>');
    write('<TD ALIGN=LEFT>Interest Rate</TD>');
    write('<TD ALIGN=LEFT BGCOLOR=#CACACA>' + (parseInt(Rate*1200000) / 1000).toString() + '%</TD>');

    write('<TD WIDTH=30></TD>');

    write('<TD ALIGN=LEFT>Monthly Payment</TD>');
    write('<TD ALIGN=LEFT BGCOLOR=#CACACA>$' + Payment.toString() + '</TD>');

    write('</TR>');

    write('</TABLE>');

    // ----------------------------
    // Write the results in a table
    // ----------------------------
    writeln('<TABLE BORDER=0>');
    writeln('<TR><TD COLSPAN=5><HR></TD></TR>');
    write('<TR><TH ALIGN=RIGHT>Month</TH>');
    write('<TH ALIGN=RIGHT>&nbsp;&nbsp;Payment</TH>');
    write('<TH ALIGN=RIGHT>&nbsp;&nbsp;Interest</TH>');
    write('<TH ALIGN=RIGHT>&nbsp;&nbsp;Principal</TH>');
    writeln('<TH ALIGN=RIGHT>&nbsp;&nbsp;Balance</TH></TR>');

    // Generate the monthly payment breakdown
    Bal = LoanAmt;
    TotInterest = 0;
    for (Counter=1;  Counter <= Period;  Counter++) {
      // Calc the interest for the remaining balance
      Interest = Rate * Bal;
      TotInterest += Interest;

      // Calculate the amount of principal paid this month
      Principal = Payment - Interest;

      // Reduce the balance
      Bal -= Principal;

      if (Bal < 0) {
        Principal += Bal;
        Bal = 0;
      }

      write('<TR><TD ALIGN=RIGHT>' + Counter + '</TD>');
      write('<TD ALIGN=RIGHT>&nbsp;&nbsp;' + ValToMoney(Payment, 1) + '</TD>');
      write('<TD ALIGN=RIGHT>&nbsp;&nbsp;' + ValToMoney(Interest, 0) + '</TD>');
      write('<TD ALIGN=RIGHT>&nbsp;&nbsp;' + ValToMoney(Principal, 0) + '</TD>');
      writeln('<TD ALIGN=RIGHT>&nbsp;&nbsp;' + ValToMoney(Bal, 0) + '</TD></TR>');
    }

    write('<TR><TD COLSPAN=5><HR></TD></TR>');

    write('<TR><TD COLSPAN=2>Total Interest</TD>');
    write('<TD>&nbsp;&nbsp;' + ValToMoney(TotInterest, 0) + '</TD></TR>');
    writeln('</TABLE>');

    writeln('</CENTER></BODY></HTML>');
    close();
  }
  return;
}

document.write('<!-- End hiding the script -->');

//-->