function calculateA() 

{

  var price = parseNumber(document.Mortgage.salesPrice.value);

  var downpmt = parseNumber(document.Mortgage.downPayment.value);

  var rate = parseNumber(document.Mortgage.annualInterestRate.value);

  var years = parseNumber(document.Mortgage.numberOfYears.value);

  var loanamt = price - downpmt;

  var nopmts = years*12;

  var morate = rate/1200;

  var mopmt = Math.round((loanamt*(morate/(1-Math.pow((1+morate), -nopmts))))*100)/100;



  document.Mortgage.loanAmount.value = commify(loanamt);

  document.Mortgage.numberOfPayments.value = commify(nopmts);

  document.Mortgage.monthlyPrincipleAndInterestPayment.value = commify(mopmt);

}



function calculateB()

{

  var PI = parseNumber(document.Mortgage.monthlyPrincipleAndInterestPayment.value);

  var SP = parseNumber(document.Mortgage.salesPrice.value);

  var LA = parseNumber(document.Mortgage.loanAmount.value);

  var MHIR = parseNumber(document.Mortgage.estimatedAnnualHomeownersInsuranceRate.value)/12;

  var MPTR = parseNumber(document.Mortgage.estimatedAnnualPropertyTaxRate.value)/12;

  var MHAF = parseNumber(document.Mortgage.estimatedMonthlyHomeownersAssociationFees.value)/12;

  var LTV = Math.round(100*LA/SP)/100;

  var J = 0;

  if((LTV <= .97) && (LTV >= .9501)) 

  {

    J = Math.round(LA * .9 / 12)/100; 

  }  

  else if((LTV <= .95) && (LTV >= .9001))

  {

    J = Math.round(LA * .78 / 12)/100;

  }

  else if((LTV <= .9) && (LTV >= .8501))

  {

    J = Math.round(LA * .52 / 12)/100;

  }

  else if((LTV <= .85) && (LTV >= .8001))

  {

    J = Math.round(LA * .32 / 12)/100;

  }

  document.Mortgage.totalEstimatedMonthlyPayment.value = commify(PI + J + MHAF + MHIR + MPTR );

}

function parseNumber(value)

{

  value = new String(value);

  value = value.replace(/[^0-9\.]/g,"");

  if(value.length == 0)

  {

    return 0;

  }

  return parseFloat(value);

}

function commify(value)

{

  value = new String(value);

  value = reverse(value);

  value = value.replace(/(\d\d\d)/,"$1,");

  value = value.replace(/,$/,"");

  return reverse(value);

}

function reverse(value)

{

  value = new String(value);

  var i;

  var reversed = new String();

  for(i = value.length-1; i >= 0; i--)

  {

    reversed = reversed.concat(value.charAt(i));

  }

  return reversed;

}