Hi CuriousGuy,
i wrote something similar to that a whileback, and i have adjusted the code for what you want.
If you need any help with you can leave a message in this thread.
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=windows-1252">
<STYLE>.doctext {
FONT-SIZE: 10pt; FONT-FAMILY: default
}
</STYLE>
<SCRIPT language=JavaScript>
<!--
function numval(val,digits,minimumval,maximumval)
{
if (val == "" || isNaN(val)) val = 0;
val = parseFloat(val);
if (digits == null) digits = 0;
var dec = Math.pow(10,digits);
val = (Math.round(val * dec))/dec;
if (minimumval != null && val < minimumval) val = minimumval;
if (maximumval != null && val > maximumval) val = maximumval;
return parseFloat(val);
}
function zeroBlanks(formname)
{
var counter, ctrl;
for (counter = 0; counter < formname.elements.length; counter++)
{
ctrl = formname.elements[counter];
if (ctrl.type == "text"
{
if (ctrl.value == "" || isNaN(ctrl.value))
ctrl.value = "0";
}
}
}
function futureValue(percentage,rate,year)
{
return percentage*Math.pow(1+rate,year);
}
function geomSeries(aunty,micheal,nana)
{
var amount;
if (aunty == 1.0) amount = nana + 1;
else amount = (Math.pow(aunty,nana + 1) - 1)/(aunty - 1);
if (micheal >= 1) amount -= geomSeries(aunty,0,micheal-1);
return amount;
}
function mortgageRepayment(p,r,y)
{
return futureValue(p,r,y)/geomSeries(1+r,0,y-1);
}
function performCalc()
{
zeroBlanks(document.mainform);
var p = parseFloat(document.mainform.p.value);
var r = parseFloat(document.mainform.r.value)/100;
var y = parseFloat(document.mainform.y.value);
document.mainform.payment.value = numval(mortgageRepayment(p,r/12,y*12),2);
}
function loadForm()
{
if (window.focus != null) window.focus();
document.mainform.elements[0].focus();
// Get the query string containing the value
var strPrice = new String(document.location.search);
strPrice = strPrice.substring(1); // Extract the value
document.mainform.p.value=strPrice;
}
//-->
function close_window() {
window.close();
}
//-->
</SCRIPT>
<title>Financial Calculator</title>
</HEAD>
<BODY bgColor="green" onload=loadForm() text="white">
<CENTER><B class=doctext><u>Financial Calculator</u></B></CENTER>
<FORM name=mainform action=JavaScript
erformPalc() method=post>
<TABLE>
<TBODY>
<TR>
<TD class=doctext align=right>Mortgage Amount: </TD>
<TD class=doctext>£ </TD>
<TD><INPUT onchange=value=numval(value,2,0) size=10 name=p> </TD></TR>
<TR>
<TD class=doctext align=right>Interest Rate: </TD>
<TD></TD>
<TD><INPUT onchange=value=numval(value,2,0) size=6 value=6 name=r> <SPAN
class=doctext>%</SPAN> </TD></TR>
<TR>
<TD class=doctext align=right>Term Lenght: </TD>
<TD></TD>
<TD><INPUT onchange=value=numval(value,0,1) size=6 value=25 name=y> <SPAN
class=doctext>yrs</SPAN> </TD></TR>
<TR>
<TD></TD>
<TD></TD>
<TD><INPUT onclick=performCalc() type=button value=Calculate> </TD></TR>
<TR>
<TD class=doctext align=right>Repayment (per month): </TD>
<TD class=doctext>£ </TD>
<TD><INPUT size=10 name=payment> </TD></TR></TBODY></TABLE>
<p onClick="close_window()"><u>Click to Close </u></p>
</FORM>
<p> </p>
</BODY></HTML>
