var irate, years, term, downp, mi, cmi, tprinc, princ, paym, cpaym, osp, v, downr, comp;



function calcPaym () {

	tprinc = round2d(parseFloat(document.smpc.tprinc.value));

	downp = .01*parseFloat(document.smpc.downp.value);

	downr = ceil2d(downp*tprinc);

	princ = tprinc-downr;

	

	document.smpc.princ.value= fmt2d(princ,0);

	document.smpc.downr.value= fmt2d(downr,0);

	

	irate = .01*parseFloat(document.smpc.percent.value);

	years=parseFloat(document.smpc.years.value);

	term = parseFloat(document.smpc.term.value);

	if (term > years) term=years;

	

	if (term==0 || years==0||irate<.0001||princ<1)

		{alert("values must be numeric");}

	else {

		mi = Math.pow(1+ irate/2,1/6);

		//mi = 1+(irate/12);

		v = 1/mi;

		paym = ceil2d(princ*(mi-1)/(1-Math.pow(mi,-(years*12))));

		osp = (princ-(v*paym*(1-Math.pow(v,12*term)))/(1-v))/Math.pow(v,12*term);

		if(osp<0)osp = 0;

 

		document.smpc.paym.value=fmt2d(paym,0);

		document.smpc.owed.value= fmt2d(osp,0);

		}

	}



function round2d(n) {return(.01* Math.round(100*n));}

function floor2d(n) {return(.01* Math.floor(100*n));}

function ceil2d(n) {return(.01* Math.ceil(100*n));}



// format number n as string width w with 2 decimal places

function fmt2d(n,w) {

	var work,dp,sl,dl;

	

	work = ""+floor2d(n); // force only 2 decimals

	sl=work.length;

	

	if(-1 == (dp = work.indexOf("."))) work=work+".00";

	else if(3 > sl-dp) work = work+".00".substring(sl-dp,3);

	sl = work.length;

	if(0 != w && w !=sl)

		if(w<sl)

			{work = "*";for(sl=1;sl<w;sl++)work=work+"*";}

      	else

      		for (;sl<w;sl++) work=" "+work;

	return work;

	}