Untitled

<html>
<head>
<script type="text/javascript">

function checkForZero (field) {
if (field.value == 0 || field.value.length == 0)
{ alert ("NO ZERO'S!!!");
  field.focus(); }
else
 calculatePayment (field.form);
 }


function show_prompt ()
{
var interestRate=prompt ("Enter interest Rate (%)");

var lengthLoan=prompt ("Enter length of the loan (Years)");

var loanAmount=prompt ("Enter amount of loan($)");


var n = interestRate/12*lengthLoan;

var m1 = loanAmount * math.pow ((1+interestRate) , n);

var m2 = m1 * interestRate;

var m3 = math.pow((1+interestRate) , n)-1;

var m = m2 / m3;

var mortgage=prompt (m);


}


</script>
</head>
<body>


<input type="button" onclick="show_prompt()" value="Calculate" />


</body>
</html>