CODE FOR FUNCTION PV
<script language="JavaScript">
<!--
// Function to calculate present value of an investment..
// Parameters are rate, total number of periods, payment made each period, future value and type (when payments are due)
function pv(rate, per, nper, pmt, fv)
{
nper = parseFloat(nper);
pmt = parseFloat(pmt);
fv = parseFloat(fv);
rate = eval((rate)/(per * 100));
if (( pmt == 0 ) || ( nper == 0 )) {
alert("Why do you want to test me with zeros?");
return(0);
}
if ( rate == 0 ) // Interest rate is 0
{
pv_value = -(fv + (pmt * nper));
}
else
{
x = Math.pow(1 + rate, -nper);
y = Math.pow(1 + rate, nper);
pv_value = - ( x * ( fv * rate - pmt + y * pmt )) / rate;
}
pv_value = conv_number(pv_value,2);
return (pv_value);
}
function conv_number(expr, decplaces)
{ // This function is from David Goodman's Javascript Bible.
var str = "" + Math.round(eval(expr) * Math.pow(10,decplaces));
while (str.length <= decplaces) {
str = "0" + str;
}
var decpoint = str.length - decplaces;
return (str.substring(0,decpoint) + "." + str.substring(decpoint,str.length));
}
// --></script>