<html>
<head> Mortgage Program
<title> Mortgage Program
</title>
<script language = "JavaScript">
function Calc(myform)
{
var mortAmount=document.forms.MortCalc.Amount.value;
var mortAmount=parseInt(mortAmount,10);
if (isNaN(mortAmount))
{
alert("The loan amount is not a number!");
document.forms.MortCalc.Amount.value="
";
document.forms.MortCalc.Amount.focus();
}
else {
var mortRate=document.forms.MortCalc.Rate.value;
var mortRate=parseFloat(mortRate);
if (isNaN(mortRate))
{
alert("The interest rate is not a number!");
document.forms.MortCalc.Rate.value="
";
document.forms.MortCalc.Rate.focus();
}
else {
var mortYears=document.forms.MortCalc.Years.value;
var mortYears=parseInt(mortYears,10);
if (isNaN(mortYears))
{
alert("The Number of Years is not a number!");
document.forms.MortCalc.Years.value="
";
document.forms.MortCalc.Years.focus();
}
}
}
document.forms.MortCalc.Payment.value=monthly(mortAmount,mortRate,mortYears);
document.forms.MortCalc.Payment.value=dollarFormat(document.forms.MortCalc.Payment.value);
}
function
monthly(mortAmount,mortRate,mortYears)
{
var Irate=mortRate/1200;
var Pmts=mortYears*12;
var Loan=mortAmount;
return Loan * (Irate / (1 - (1 / Math.pow(1+Irate,Pmts))));
}
function dollarFormat(valuein)
{
var formatStr="";
var Outdollars="";
var decipos=valuein.indexOf(".");
if (decipos==-1)
{
decipos=valuein.length;
}
var dollars=valuein.substring(0,decipos);
var dollen=dollars.length;
if (dollen>3)
{
while (dollen>0)
{
tDollars=dollars.substring(dollen-3,dollen);
if (tDollars.length==3)
{
Outdollars=","+tDollars+Outdollars;
dollen=dollen-3;
}
else {
Outdollars=tDollars+Outdollars;
dollen=0
}
}
if (Outdollars.substring(0,1)==",")
{
dollars=Outdollars.substring(1,Outdollars.length);
}
else {
dollars=Outdollars;
}
}
var cents=valuein.substring(decipos+1,decipos+3);
if (cents=="")
{
cents="00";
}
var formatStr="$"+dollars+"."+cents;
return formatStr;
}
</script>
</head>
<FORM id="MortCalc">
<TABLE>
<TR>
<TD>Amount
of Mortgage:</TD>
<TD><INPUT Type="text" Name="Amount"
value=" " Size="9"></TD>
</TR>
<TR>
<TD>Interest Rate as % (e.g. 7.9):</TD>
<TD><INPUT Type="text" Name="Rate"
value=" " Size="9"></TD>
</TR>
<TR>
<TD>Number
of Years:</TD>
<TD><INPUT Type="text" Name="Years"
value=" " Size="9"></TD>
</TR>
<TR>
<TD>Monthly Payment:</TD>
<TD><INPUT Type="text" Name="Payment"
value=" " Size="12"></TD>
</TR>
<TR>
<TD><INPUT Type="Button" value="Calculate"
onclick="Calc(MortCalc)">
<INPUT
Type="Reset"></TD>
</TR>
</TABLE>
</FORM>
</html>