//*******************************************
//DO NOT REMOVE THIS COPYWRITE INFO!
//Spending Cost Calculator
//2002 Daniel C. Peterson ALL RIGHTS RESERVED
//Created: 01/29/2002
//Last Modified: 05/22/2002
//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 #:5782-1237-25-1198
//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 formatNumber(num) {

var isNeg=0;

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

    
	onum=Math.round(num*100)/100;
		
	integer=Math.floor(onum);

	if (Math.ceil(onum) == integer) {
		decimal="00";
	} else{
		decimal=Math.round((onum-integer)*100)
	}
	decimal=decimal.toString();
	if (decimal.length<2) decimal="0"+decimal;

	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;

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

	return finNum;
}


function computeForm(form)

{

if(form.principal.value == "" || form.principal.value == 0) {
   alert("Please enter the dollar amount of a purhcase you are contemplating.");
   form.principal.focus();
} else
if(form.interest.value == "" || form.interest.value == 0) {
   alert("Please enter the annual interest rate you would expect to earn if you invested the money rather than spend it.");
   form.interest.focus();
} else
if(form.payments.value == "" || form.payments.value == 0) {
   alert("Please enter the number of years you would allow your investment to grow.");
   form.payments.focus();
} else {


    var i = stripNum(form.interest.value);

    if (i > 1.0) {

        i = i / 100.0;

    }

    i /= 12;


   var pow = stripNum(form.principal.value);
var displayPrin = stripNum(form.principal.value);

var Vpayments = stripNum(form.payments.value );
    
    for (var j = 0; j < Vpayments*12; j++)

        pow = (pow * i) + (pow *1);

    var Vfv = pow;

    form.fv.value = "$" + formatNumber(pow);

    var Vtotalint = (Vfv - displayPrin);

form.totalint.value = "$" + formatNumber(Vtotalint);

form.summary.value = "If you spend $" + formatNumber(displayPrin) + " on an unnecessary product or service, and you could otherwise invest that money for " + Vpayments + " years, then spending the $" + formatNumber(displayPrin) + " could cost you $"  + formatNumber(Vtotalint) + " in forgone interest earnings. This would bring the real price-tag of what you are spending your money on to $" + formatNumber(pow) + ". So the question you should ask yourself is, \"Is what I am spending my money on worth $" + formatNumber(pow) + "?\"";

}

}