function floor(number)
{
  return Math.floor(number*Math.pow(10,2))/Math.pow(10,2);
}

function dosum()
{
  var oRate = document.getElementById("rate");
  var oTerm = document.getElementById("term");
  var oAmount = document.getElementById("amount");
  var oPayment = document.getElementById("payment");
  var oDown = document.getElementById("down");
  
  var val = oAmount.value * ((100 - oDown.value) / 100)
  //var val = oAmount.value
  var mi = oRate.value / 1200;
  var base = 1;
  var mbase = 1 + mi;
  var terms = oTerm.value
 var end = ""
  for (i=0; i<(terms * 12); i++)
  {
    base = base * mbase
  }
  var Num = "" + floor(val * mi / ( 1 - (1/base)))
    
  if (Num.indexOf(".")>0)
	{
		arr = Num.split(".")
		if (arr[1].length==1) end = "0"
	}
	else{
		end = ".00"
	}
	
		Num = Num + end

	if (document.all) {
	oPayment.innerText = '$'+Num
	} else {
	oPayment.textContent  = '$'+Num
	}
}