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

function dosum()
	{
	var mi = document.mtgcalc.IR.value / 1200;
	var base = 1;
	var mbase = 1 + mi;
	for (i=0; i<document.mtgcalc.YR.value * 12; i++)
		{
		base = base * mbase;
		}

	document.mtgcalc.PI.value = format(floor(document.mtgcalc.LA.value * mi / ( 1 - (1/base))))
	document.mtgcalc.MT.value = format(floor(document.mtgcalc.AT.value / 12))
	document.mtgcalc.MI.value = format(floor(document.mtgcalc.AI.value / 12))
	var dasum = document.mtgcalc.LA.value * mi / ( 1 - (1/base)) +
		document.mtgcalc.AT.value / 12 + document.mtgcalc.AI.value / 12;

 	document.mtgcalc.MP.value = format(floor(dasum));
	}

function format(num)
	{
	num = Math.floor(num*100+0.50000000001);
	cents = num%100;
	num = Math.floor(num/100).toString();
	if(cents<10)
	cents = "0" + cents;
	for (var i = 0; i < Math.floor((num.length-(1+i))/3); i++)
	num = num.substring(0,num.length-(4*i+3))+','+
	num.substring(num.length-(4*i+3));
	return ("$" + num + '.' + cents);
	}