Source for JavaScript Demo calc.html

<HEAD>
<TITLE>EIW JavaScript Demo - Calculator</TITLE>
<SCRIPT>
function calcpayment() {
   var amt = document.frm.amt.value;
   var ir = document.frm.ir.value / 1200;
   var term = document.frm.term.value * 12;
   var total=1;

   for (i=0;i<term;i++) {
      total = total * (1 + ir);
   }
  mp = amt * ir / ( 1 - (1/total));
  document.frm.payment.value = mp;
  document.frm.total.value = mp * term ;
}
</SCRIPT>
</HEAD>

<BODY BGCOLOR=WHITE>
<HTML>

<H2 ALIGN=CENTER>JavaScript Calculator</H2>
<HR>
<FORM NAME=frm>
<TABLE>
<TR>
  <TD>Mortgage Amount</TD>
  <TD><INPUT TYPE=TEXT Name=amt></TD>
</TR>

<TR>
  <TD>Yearly Interest Rate</TD>
  <TD><INPUT TYPE=TEXT Name=ir></TD>
</TR>

<TR>
  <TD>Term (in years)</TD>
  <TD><INPUT TYPE=TEXT Name=term></TD>
</TR>
<TR><TD COLSPAN=2><HR></TD></TR>
 <TR>
  <TD>Monthly Payment:</TD>
  <TD><INPUT TYPE=TEXT Name=payment></TD>
</TR>

 <TR>
  <TD>Total Payments:</TD>
  <TD><INPUT TYPE=TEXT Name=total></TD>
</TR>
</TABLE>
<INPUT TYPE=BUTTON VALUE="Press to calculate monthly payment"
  onclick="calcpayment();">

</FORM>