//*******************************************
//DO NOT REMOVE THIS COPYWRITE INFO!
//Interest Only Vs. Principal & Interest Payment Calculator
//2006 Daniel C. Peterson ALL RIGHTS RESERVED
//Created: 06/06/2006
//Last Modified: 06/06/2006
//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 #:4973-1138-142-1097
//Commercial Licence Date:2007-10-08
//*******************************************



function stripNum(num) {

var iPercent
var iDollar
var iSpace
var iComma
var numLength = num.length

//lalalla Line #114

if(numLength > 0) {

   num=num.toString();

   iPercent = num.indexOf("%");
   if(iPercent >= 0) {
      num=num.substring(0,iPercent) + "" + num.substring(iPercent + 1,numLength);
      numLength=num.length;
      }
   iDollar = num.indexOf("$");
   if(iDollar >= 0) {
      num=num.substring(0,iDollar) + "" + num.substring(iDollar + 1,numLength);
      numLength=num.length;
      }
   iSpace = num.indexOf(" ");
   if(iSpace >= 0) {
      num=num.substring(0,iSpace) + "" + num.substring(iSpace + 1,numLength);
      numLength=num.length;
      }
   iComma = num.indexOf(",");
   if(iComma >= 0) {
      while(iComma >=1) {
         num=num.substring(0,iComma) + "" + num.substring(iComma + 1,numLength);
         numLength=num.length;
         iComma = num.indexOf(",");
      }
      }

      num = eval(num);


} else {

num = 0;

}

return num;

}




function computeMonthlyPayment(prin, numPmts, intRate) {

var pmtAmt = 0;

if(intRate == 0) {
   pmtAmt = prin / numPmts;
} else {
   
   if (intRate >= 1.0) {
     intRate = intRate / 100.0;
   }
   intRate /= 12;

   var pow = 1;
   for (var j = 0; j < numPmts; j++)
      pow = pow * (1 + intRate);

   pmtAmt = (prin * pow * intRate) / (pow - 1);

}

return pmtAmt;

}




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 == null || form.principal.value.length == 0) {
   alert("Please enter the loan's principal amount.");
   form.principal.focus();
} else
if (form.interest.value == null || form.interest.value.length == 0) {
   alert("Please enter the loan's annual interest rate.");
   form.interest.focus();
} else
if (form.num_years.value == null || form.num_years.value.length == 0) {
   alert("Please enter the loan's term in years.");
   form.num_years.focus();
} else {

   var Vprincipal = stripNum(form.principal.value);

   var Vint_rate = stripNum(form.interest.value);
   var i = Vint_rate;
   i = i / 100;
   i = i / 12;

   var Vnum_years = stripNum(form.num_years.value);
   var Vnum_pmts = Vnum_years * 12;

   var Vio_payment = Vprincipal * i;

   form.io_payment.value = "$" + formatNumberDec(Vio_payment,2,1);

   var Vpi_payment = computeMonthlyPayment(Vprincipal, Vnum_pmts, Vint_rate);
   form.pi_payment.value = "$" + formatNumberDec(Vpi_payment,2,1);


   }
}

function clearResults(form) {

   form.io_payment.value = "";
   form.pi_payment.value = "";
}