function calculate() {
 var nInvoice = parseFloat($('#cal_invoice').val());
 var nDown = parseFloat($('#cal_down').val());
 
 //var nP = $('#cal_province').selectedIndex;
 //var nProvtax = parseFloat(document.loan.cal_province[nP].value);
 
 var nProvtax = 8; //ontario only
 
 //var nN = document.loan.length.selectedIndex;
 var nTerm = $('#cal_length').val(); 
 //var nTerm = parseFloat(document.loan.length[nN].value);
 
 var nRate = parseFloat($('#cal_rate').val()); 
 var nTrade = parseFloat($('#cal_trade').val());
 var nProcentage = 8; //parseFloat(document.calculator.cal_procentage[nProvtax]);
 var nGst = 0;
 var nPst = 0;
 
 /*
 if (nP == 0) {
   nGst = ((nInvoice - nTrade)/100)* 5;
   nPst = (((nInvoice - nTrade)+ nGst)/100) * nProvtax;
 }
 else if (nP == 1) {
  nGst = 0;
  nPst = ((nInvoice - nTrade)/100) * nProvtax;
 }
 else if (nP == 2) {
   nGst = 0;
   nPst = ((nInvoice - nTrade)/100) * nProvtax;
 }
  else if (nP ==3) {
   nGst = 0;
   nPst = ((nInvoice - nTrade)/100) * nProvtax;
   name="H.S.T.";
 }
 else if (nP == 4) {
  nGst = ((nInvoice - nTrade)/100) * 5;
  nPst = (((nInvoice - nTrade) + nGst) / 100) * nProvtax;
 
 }
 else if (nP == 7) {
  nGst = ((nInvoice - nTrade)/ 100) * 5;
  nPst = (nInvoice / 100) * nProvtax;
  }
  else if (nP == 13){
  nGst = 0;
  }
 else  {
 */
  nGst = ((nInvoice - nTrade ) / 100) * 5;
  nPst = ((nInvoice - nTrade) /100) * nProvtax;
 //} 
 
 var nFinanced =  (nInvoice  + nGst +nPst) - (nTrade + nDown);

  var nI = nRate / 100 / 12;

  var nY = Math.pow(1 + nI, nTerm);

 
  var nPayment = (nFinanced * nY * nI) / (nY -1);
  var nInterest  = (nPayment * nTerm) - nFinanced;
  
  
  $('#cal_interest').val(Math.round(nInterest));
  //document.calculator.cal_interest.value =Math.round(nInterest);
  
  $('#cal_payment').val(Math.round(nPayment));
  //document.calculator.cal_payment.value=Math.round(nPayment);
  
  $('#cal_financed').val(Math.round(nFinanced));
  //document.calculator.cal_financed.value=Math.round(nFinanced);
  
  $('#cal_gst').val(Math.round(nGst));
  //document.calculator.cal_gst.value=Math.round(nGst);
  
  $('#cal_pst').val(Math.round(nPst));

  //document.calculator.cal_pst.value=Math.round(nPst);
  //document.calculator.cal_procentage.value=Math.round(nProvtax);
 }
 
$(document).ready(function() {
	
	$('#calculator input, #calculator select').change(function(e) {
		calculate();
	});
	$('#calculate_loan').click(function(e) {
		calculate();
	});
	
	calculate();
});