function ValidateData(form)
	{
	var LoanAmt, InterestRate, Term;

	LoanAmt = form.txtLoanAmt.value;
	InterestRate = form.txtInterestRate.value;
	Term = form.txtTerm.value;
	
	if ( isNaN(LoanAmt) || eval(LoanAmt) <= 0 || LoanAmt == "") 
		{
		alert("Loan Amount must be a number > 0");
        form.txtLoanAmt.value = "";
		form.txtLoanAmt.focus();
		return false; 
		}
		
	if ( isNaN(InterestRate) || InterestRate == "")
		{
		alert("Interest Rate must be a number");
		form.txtInterestRate.value = "";
		form.txtInterestRate.focus();
		return false;
		}
				
	if ( isNaN(Term) || eval(Term) <= 0 || Term == "")
		{
		alert("Term of years must be a number > 0");
		form.txtTerm.value = "";
		form.txtTerm.focus();
		return false;
		}	
		
	if (eval(Term) > 30)
	    {
		alert('Maximum Term is 30 years');
		return false;
		}
	  				
	if (true)
		return true;			
		
	}

var LoanAmt;
var Term;
var	InterestRate;
var MonthlyPayment;
var SPITable;

function CalculatePymt(form) 
	{
	var TotMth; 
	var MthlyInterest;
	var i, j;
	
	form.txtMthPymt.value = ""
	
	if (ValidateData(form)==false)
	{
		return;
	}

 	LoanAmt = eval(form.txtLoanAmt.value);
 	Term = eval(form.txtTerm.value);
	InterestRate = eval(form.txtInterestRate.value);

	TotMth = Term * 12;
	MthlyInterest = eval(InterestRate) / 100 / 12;

	MonthlyPayment = (LoanAmt * MthlyInterest) / (1 - (1 / Math.pow(1 + MthlyInterest, TotMth)));
	form.txtMthPymt.value = perfect(Round(MonthlyPayment));
	
	return;
}

function perfect(number) {
	if (number < 0)	number = 0;
	return FormatDigit(number);
	}