function stripNum(num) {

   num=num.toString();


   var len = num.length;
   var rnum = "";
   var test = "";
   var j = 0;

   var b = num.substring(0,1);
   if(b == "-") {
      rnum = "-";
   }

   for(i = 0; i <= len; i++) {

      b = num.substring(i,i+1);

      if(b == "0" || b == "1" || b == "2" || b == "3" || b == "4" || b == "5" || b == "6" || b == "7" || b == "8" || b == "9" || b == ".") {
         rnum = rnum + "" + b;

      }

   }

   if(rnum == "" || rnum == "-") {
      rnum = 0;
   }

   rnum = Number(rnum);

   return rnum;

}



function FVsingleDep(prin, intRate, numMonths, numCompPerYr) {

var i = 0;
var intEarn = 0;
var singleFV = prin;

if(intRate >= 1) {
   intRate /= 100;
}

if(numCompPerYr == "" || numCompPerYr == 0) {
   numCompPerYr = 12;
}
intRate /= numCompPerYr;

var numPeriods = numMonths / 12 * numCompPerYr;

singleFV = Math.pow((eval(1) + eval(intRate)), numPeriods) * singleFV;

return singleFV;

}



function formatNumberDec(num, places, comma) {

var isNeg=0;

    if(num < 0) {
       num=num*-1;
       isNeg=1;
    }

    var myDecFact = 1;
    var myPlaces = 0;
    var myZeros = "";
    while(myPlaces < places) {
       myDecFact = myDecFact * 10;
       myPlaces = eval(myPlaces) + eval(1);
       myZeros = myZeros + "0";
    }
    
	onum=Math.round(num*myDecFact)/myDecFact;
		
	integer=Math.floor(onum);

	if (Math.ceil(onum) == integer) {
		decimal=myZeros;
	} else{
		decimal=Math.round((onum-integer)* myDecFact)
	}
	decimal=decimal.toString();
	if (decimal.length<places) {
        fillZeroes = places - decimal.length;
	   for (z=0;z<fillZeroes;z++) {
        decimal="0"+decimal;
        }
     }

   if(places > 0) {
      decimal = "." + decimal;
   }

   if(comma == 1) {
	integer=integer.toString();
	var tmpnum="";
	var tmpinteger="";
	var y=0;

	for (x=integer.length;x>0;x--) {
		tmpnum=tmpnum+integer.charAt(x-1);
		y=y+1;
		if (y==3 & x>1) {
			tmpnum=tmpnum+",";
			y=0;
		}
	}

	for (x=tmpnum.length;x>0;x--) {
		tmpinteger=tmpinteger+tmpnum.charAt(x-1);
	}


	finNum=tmpinteger+""+decimal;
   } else {
      finNum=integer+""+decimal;
   }

    if(isNeg == 1) {
       finNum = "-" + finNum;
    }

	return finNum;
}


function computeForm(form)

{

if(form.principal.value == "") {
   alert("Please enter the amount of the CD.");
   form.principal.focus();
} else 
if(form.intRate.value == "") {
   alert("Please enter the annual interest rate.");
  form.intRate.focus();
} else
if(form.months.value == "") {
   alert("Please enter the number of months between 1 and 120.");
   form.months.focus();
} else {

   var Vprincipal = stripNum(form.principal.value);
   var VintRate = stripNum(form.intRate.value);
   var Vmonths = stripNum(form.months.value);
   var VnumCompPerYr = form.compoundInt.options[form.compoundInt.selectedIndex].value;

var Vfv = FVsingleDep(Vprincipal, VintRate, Vmonths, VnumCompPerYr);
form.fv.value = "$" + formatNumberDec(Vfv,2,1);

var Vtotalint = eval(Vfv) - eval(Vprincipal);
form.totalint.value = "$" + formatNumberDec(Vtotalint,2,1);

var VoneYrFv = FVsingleDep(Vprincipal, VintRate, 12, VnumCompPerYr);
var VoneYrYield = eval(VoneYrFv) - eval(Vprincipal);
var Vapy = VoneYrYield / Vprincipal * 100;
form.apy.value = formatNumberDec(Vapy,3,0) + "%";

}

}