//*******************************************
//DO NOT REMOVE THIS COPYWRITE INFO!
//Taxable Vs. Tax-deferred Calculator
//2003 Daniel C. Peterson ALL RIGHTS RESERVED
//Created: 01/18/2003
//Last Modified: 01/22/2007
//This script may not be copied, edited, distributed or reproduced
//without express written permission from
//Daniel C. Peterson of Web Winder Website Services
//For commercial use rates, contact:
//Dan Peterson:
//Web Winder Website Services
//P.O. Box 11
//Bemidji, MN  56619
//dan@webwinder.com
//http://www.webwinder.com
//Commercial User Licence #:5782-1237-93-1198
//Commercial Licence Date:2008-09-11
//*******************************************



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 ATEarnSingleDep(prin, intRate, numMonths, numCompPerYr, fedStTaxRate) {

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

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

if(fedStTaxRate == "" || fedStTaxRate == 0) {
   fedStTaxRate = 0;
} else {
   if(fedStTaxRate >= 1) {
      fedStTaxRate /= 100;
   }
}

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

var numPeriods = numMonths / 12 * numCompPerYr;

var accumAnnInt = 0;
var accumTotEarn = 0;
var tax = 0;

for(i=1; i <= numPeriods; i++) {
   intEarn = singleFV * intRate;
   accumAnnInt = eval(accumAnnInt) + eval(intEarn);
   accumTotEarn = eval(accumTotEarn) + eval(intEarn);
   singleFV = eval(singleFV) + eval(intEarn);

   if(i % numCompPerYr == 0) {
      tax = fedStTaxRate * accumAnnInt;
      accumTotEarn = eval(accumTotEarn) - eval(tax);
      singleFV = eval(singleFV) - eval(tax);
      accumAnnInt = 0;
   }
   
}

return accumTotEarn;

}



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 ATPEarnSingleDep(prin, intRate, numMonths, numCompPerYr, fedStTaxRate, percTaxable) {

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

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

if(fedStTaxRate == "" || fedStTaxRate == 0) {
   fedStTaxRate = 0;
} else {
   if(fedStTaxRate >= 1) {
      fedStTaxRate /= 100;
   }
}

if(percTaxable == "" || percTaxable == 0) {
   percTaxable = 0;
} else {
   if(percTaxable >= 1) {
      percTaxable /= 100;
   }
}

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

var numPeriods = numMonths / 12 * numCompPerYr;

var accumAnnInt = 0;
var accumTotEarn = 0;
var tax = 0;
var taxable = 0;

for(i=1; i <= numPeriods; i++) {
   intEarn = singleFV * intRate;
   accumAnnInt = eval(accumAnnInt) + eval(intEarn);
   accumTotEarn = eval(accumTotEarn) + eval(intEarn);
   singleFV = eval(singleFV) + eval(intEarn);

   if(i % numCompPerYr == 0) {
      taxable = accumAnnInt * percTaxable;
      tax = fedStTaxRate * taxable;
      accumTotEarn = eval(accumTotEarn) - eval(tax);
      singleFV = eval(singleFV) - eval(tax);
      accumAnnInt = 0;
   }
   
}

return accumTotEarn;

}



function computeAnnYieldSS(myYears, myPrin, myFV, myGuess, myCPY) {

var myDecRate = 0;

if(myGuess.length == 0 || myGuess == 0) {
   var myDecGuess = 6;
   } else {
   var myDecGuess = myGuess;
   if(myDecGuess >= 1) {
      myDecGuess = myDecGuess /100;
      }
   }

var myDecRate = myDecGuess / myCPY;
var myNewFV = 0;
var pow = 1;
var j = 0;

var myNPR = myYears * myCPY;

for (j = 0; j < myNPR; j++) {
   pow = pow * (eval(1) + eval(myDecRate));
}

myNewFV = (myPrin * pow);

//2 DEC PLACE AMOUNT
var decPlace2Rate = (eval(myDecGuess) + eval(.01)) / myCPY;
var decPlace2Amt = 0;
pow = 1;
j=0;
for (j = 0; j < myNPR; j++) {
   pow = pow * (eval(1) + eval(decPlace2Rate));
}
var decPlace2FV = (myPrin * pow);
decPlace2Amt = eval(decPlace2FV) - eval(myNewFV);

//3 DEC PLACE AMOUNT
var decPlace3Rate = (eval(myDecGuess) + eval(.001)) / myCPY;
var decPlace3Amt = 0;
pow = 1;
j=0;
for (j = 0; j < myNPR; j++) {
   pow = pow * (eval(1) + eval(decPlace3Rate));
}
var decPlace3FV = (myPrin * pow);
decPlace3Amt = eval(decPlace3FV) - eval(myNewFV);

//4 DEC PLACE AMOUNT
var decPlace4Rate = (eval(myDecGuess) + eval(.0001)) / myCPY;
var decPlace4Amt = 0;
pow = 1;
j=0;
for (j = 0; j < myNPR; j++) {
   pow = pow * (eval(1) + eval(decPlace4Rate));
}
var decPlace4FV = (myPrin * pow);
decPlace4Amt = eval(decPlace4FV) - eval(myNewFV);

//5 DEC PLACE AMOUNT
var decPlace5Rate = (eval(myDecGuess) + eval(.00001)) / myCPY;
var decPlace5Amt = 0;
pow = 1;
j=0;
for (j = 0; j < myNPR; j++) {
   pow = pow * (eval(1) + eval(decPlace5Rate));
}
var decPlace5FV = (myPrin * pow);
decPlace5Amt = eval(decPlace5FV) - eval(myNewFV);

var myPmtDiff = 0;

if(myNewFV < myFV) {

   while(myNewFV < myFV) {

      myPmtDiff = eval(myFV) - eval(myNewFV);
      if(myPmtDiff > decPlace2Amt) {
         myDecRate = eval(myDecRate) + eval(.01 / myCPY);
      } else
      if(myPmtDiff > decPlace3Amt) {
         myDecRate = eval(myDecRate) + eval(.001 / myCPY);
      } else
      if(myPmtDiff > decPlace4Amt) {
         myDecRate = eval(myDecRate) + eval(.0001 / myCPY);
      } else
      if(myPmtDiff > decPlace5Amt) {
         myDecRate = eval(myDecRate) + eval(.00001 / myCPY);
      } else {
         myDecRate = eval(myDecRate) + eval(.000001 / myCPY);
      }

      pow = 1
      j = 0;
      
      for (j = 0; j < myNPR; j++) {
         pow = pow * (eval(1) + eval(myDecRate));
      }
      myNewFV = (myPrin * pow);
   }

} else {


   while(myNewFV > myFV) {

      myPmtDiff = eval(myNewFV) - eval(myFV);
      if(myPmtDiff > decPlace2Amt) {
         myDecRate = eval(myDecRate) - eval(.01 / myCPY);
      } else
      if(myPmtDiff > decPlace3Amt) {
         myDecRate = eval(myDecRate) - eval(.001 / myCPY);
      } else
      if(myPmtDiff > decPlace4Amt) {
         myDecRate = eval(myDecRate) - eval(.0001 / myCPY);
      } else
      if(myPmtDiff > decPlace5Amt) {
         myDecRate = eval(myDecRate) - eval(.00001 / myCPY);
      } else {
         myDecRate = eval(myDecRate) - eval(.000001 / myCPY);
      }

      pow = 1
      j = 0;
      
      for (j = 0; j < myNPR; j++) {
         pow = pow * (eval(1) + eval(myDecRate));
      }
      myNewFV = (myPrin * pow);
   }


}

myDecRate = myDecRate * myCPY * 100;

return myDecRate;

}

function computeForm(form)

{

if(form.principal.value == "") {
   alert("Please enter the amount invested.");
   form.principal.focus();
} else 
if(form.intRate.value == "") {
   alert("Please enter the expected annual rate of return.");
  form.intRate.focus();
} else
if(form.years.value == "") {
   alert("Please enter the number of years the amount will be invested for.");
   form.years.focus();
} else
if(form.taxRate.value == "") {
   alert("Please enter your marginal tax rate.");
   form.taxRate.focus();
} else
if(form.percentTaxable.value == "") {
   alert("Please enter the percentage of the tax-deferred earnings that will be taxable.");
   form.percentTaxable.focus();
} else {

   var Vprincipal = stripNum(form.principal.value);
   var VintRate = stripNum(form.intRate.value);
   var Vyears = stripNum(form.years.value);
   var Vmonths = Vyears * 12;
   var VnumCompPerYr = 1;
   var VtaxRate = stripNum(form.taxRate.value);
   var VpercentTaxable = stripNum(form.percentTaxable.value);

var VtaxableEarnings = ATEarnSingleDep(Vprincipal, VintRate, Vmonths, VnumCompPerYr, VtaxRate);

var VtaxableFV = eval(Vprincipal) + eval(VtaxableEarnings);
form.taxableFV.value = "$" + formatNumberDec(VtaxableFV,2,1);


var VdeferredEarnings = ATPEarnSingleDep(Vprincipal, VintRate, Vmonths, VnumCompPerYr, VtaxRate, VpercentTaxable);

var VdeferredFV = eval(Vprincipal) + eval(VdeferredEarnings);

form.deferredFV.value = "$" + formatNumberDec(VdeferredFV,2,1);


var VtaxableAnnYield = computeAnnYieldSS(Vyears, Vprincipal, VtaxableFV, 6, 1);
form.taxableAnnYield.value = formatNumberDec(VtaxableAnnYield,2,0) + "%";

var VdeferredAnnYield = computeAnnYieldSS(Vyears, Vprincipal, VdeferredFV, 6, 1);
form.deferredAnnYield.value = formatNumberDec(VdeferredAnnYield,2,0) + "%";


}

}

function clearResults(form) {

form.taxableFV.value = "";
form.deferredFV.value = "";
form.taxableAnnYield.value = "";
form.deferredAnnYield.value = "";

}