var a,b,c,x1,x2;

function getValues() {
  InterestRate = document.form.x2Coef.value;
  LoanAmount = document.form.xCoef.value * signB;
  Months = document.form.endValue.value * signC;
}

function solveForX() {
  x1 = (1+InterestRate/1200);

if (InterestRate  == 0)
{
x2 = LoanAmount / Months;
}
else
{
  x2 = LoanAmount*Math.pow(x1,(Months))*(x1-1)/(Math.pow(x1,(Months))-1);
}

x2 = .01 * Math.round(100*x2);


}


function ValidateValues() {

Good = 1;

ErrorMessage = "The following values are not valid:\n";
if ( LoanAmount == "")
{
	Good = 0;
	ErrorMessage = ErrorMessage + "Loan Amount: Please fill in a Loan Amount\n";
}
else if ( !(LoanAmount >= 0))
{
	Good = 0;
	if (LoanAmount < 0)
	{
		ErrorMessage = ErrorMessage + "Loan Amount: It must be non-negative\n";
	}
	else
	{
		ErrorMessage = ErrorMessage + "Loan Amount: It must be a number\n";
	}

}

if ( InterestRate == "")
{
	Good = 0;
	ErrorMessage = ErrorMessage + "Interest Rate: Please fill in an InterestRate\n";
}
else if ( !(InterestRate >= 0))
{
	Good = 0;
	if (InterestRate < 0)
	{
		ErrorMessage = ErrorMessage + "Interest Rate: It must be non-negative\n";
	}
	else
	{
		ErrorMessage = ErrorMessage + "Interest Rate: It must be a number\n";
	}
}



if ( Months == "")
{
	Good = 0;
	ErrorMessage = ErrorMessage + "Term" + ": Please fill in a Term\n";
}
else if ( !(Months > 0))
{
	Good = 0;
	if (Months <= 0)
	{
		ErrorMessage = ErrorMessage + "Term" + ": It must be positive\n";
	}
	else
	{
		ErrorMessage = ErrorMessage + "Term: It must be a number\n";
	}
}

}

function CalcOn() {
 // document.getElementById('divCalculator').style.visibility ='hidden';
 // document.getElementById('divCalculator');
 pageDimmer = document.getElementById('ctl00_pagedimmer');
 calcBox = document.getElementById('ctl00_divCalculator');
 
 pageDimmer.style.visibility = "";
 calcBox.style.visibility = "";
 }

function SolveEq() {

  InterestRate  = document.forms[0].InterestRate.value;
  LoanAmount  = document.forms[0].LoanAmount.value;
  Months = document.forms[0].Term.value;

  // InterestRate = 5.25;
  // LoanAmount = 87200;
  // Months = 180;
  
  ValidateValues();

if (Good == 0)
{  alert(ErrorMessage);
}
else
{
     solveForX();
     if (x2.toString().indexOf('.') > 0 &&
        x2.toString().length > x2.toString().indexOf('.') + 2)
        {
            x4 = (x2+.000001).toString().substring(0, 
            (x2+.000001).toString().indexOf('.') + 3);

             document.getElementById('PaymentAmount').innerHTML = x4;
        }
    else
    {
        document.getElementById('PaymentAmount').innerHTML = x2;   
    }        
     // alert('456.1124'.indexof('.'));
     
}
}