function Calculate()
{
	form = document.forms[0];
	if(IsInteger())
	{
		LoanAmount= form.LoanAmount.value;
			
		DownPayment= "0"
		AnnualInterestRate = form.InterestRate.value/100
		Years= form.NumberOfYears.value
			MonthRate=AnnualInterestRate/12
		NumPayments=Years*12
		Prin=LoanAmount-DownPayment
		
		MonthPayment=Math.floor((Prin*MonthRate)/(1-Math.pow((1+MonthRate),(-1*NumPayments)))*100)/100
			form.NumberOfPayments.value=NumPayments
		form.MonthlyPayment.value=MonthPayment
	}
}

function IsInteger()
{
  var str;
  
  //----------------- Loan Amount ---------------
    
  if (document.forms[0].LoanAmount.value == "")
  {
	document.forms[0].LoanAmount.focus();
	alert("Please enter Loan Amount.");
	return false;
  }
  else
  {
	 str = document.forms[0].LoanAmount.value;
	 for(var i = 0; i < str.length ; i++)
	 {
		if(str.charAt(i) >= 0 || str.charAt(i) <= 9 || str.charAt(i) == ".")
		{
		}
		else
		{
		document.forms[0].LoanAmount.focus();
		alert("Please enter correct Loan Amount.");
		return false;
		}
	 }
  }
  //================================================
  if (document.forms[0].InterestRate.value == "")
  {
	document.forms[0].InterestRate.focus();
	alert("Please enter Interest Rate.");
	return false;
  }
  else
  {
	str = document.forms[0].InterestRate.value;
	 for(var i = 0; i < str.length ; i++)
	 {
		if(str.charAt(i) >= 0 || str.charAt(i) <= 9 || str.charAt(i) == ".")
		{
		}
		else
		{
		document.forms[0].InterestRate.focus();
		alert("Please enter correct Interest Rate.");
		return false;
		}
	 }
  }
  //=================================================
  if (document.forms[0].NumberOfYears.value == "" || str.charAt(i) == ".")
  {
	document.forms[0].NumberOfYears.focus();
	alert("Please enter Number Of Years.");
	return false;
  }
  else
  {
	str = document.forms[0].NumberOfYears.value;
	 for(var i = 0; i < str.length ; i++)
	 {
		if(str.charAt(i) >= 0 || str.charAt(i) <= 9)
		{
		}
		else
		{
		document.forms[0].NumberOfYears.focus();
		alert("Please enter correct Number Of Years.");
		return false;
		}
	 }
  }
  
  return true;
}