browser = navigator.userAgent;
slowscriptmsg = "";
if (browser.indexOf("MSIE") > -1) {
        if (browser.indexOf("Windows 3.1") > -1) {
                if (browser.indexOf("MSIE 4.") > -1) {
                        slowscriptmsg = "<HR>Workaround for Win3.1 Explorer 4.0 users: If you encounter an alert indicating that this script is running too slowly, click \"No\" to the question, \"Do you want to abort this script?\"  Otherwise, results may be inaccurate.<HR>";
                }
        }
     var version;
     var requiredVersion = 2;
     if (typeof(ScriptEngineMajorVersion) + "" == "undefined") version = 1;
     else version = ScriptEngineMajorVersion();
     if ((version < requiredVersion) &&
          confirm("This page requires a newer version of JScript to view.  Do you want to upgrade now?"))
     {
        location.href = "http://www.microsoft.com/msdownload/scripting.htm";
     }
}

function fail() {
        document.calc.OMP.value = "--------";
        document.calc.NMP.value = "--------";
        document.calc.MONTHSAVINGS.value = "--------";
        document.calc.BREAKEVEN.value = "--------";
       // document.calc.ADDITIONALINTEREST.value = "--------";
        document.calc.NPM.value =  "--------";
        document.calc.PAYSMADEZERO.value = "--------";
        document.calc.RNP.value = "--------";
        document.calc.NTC.value = "--------";
        document.calc.RB.value = "--------";
        document.calc.OIPD.value = "--------";
        document.calc.NIPDZERO.value = "--------";
        document.calc.OIPTD.value = "--------";
        document.calc.NEWTOTINTcopy.value = "--------";
}

//temp storage for unchangeable text
temptext = "";

   function getORC() {
        var theval = parseFloat(strip(document.calc.oldrate.value))/1200;
        return(theval);
   }

   function getOTC() {
        var theval = parseFloat(document.calc.oldterm.value)*12;
        return(theval);
   }

   function getOMP() {
        var theval = parseFloat(strip(document.calc.oldamt.value)) * (getORC() / (1 - (1 / Math.pow((getORC()+1),getOTC()))));
        return(theval);
   }

   function getNPM() {
        var theval = (12*(parseInt(thisyear)-parseFloat(document.calc.oldyear.value)))+parseInt(thismonth)-parseInt(document.calc.oldmonth.options[document.calc.oldmonth.selectedIndex].value);
        return(theval);
   }

   function getRNP() {
        var theval = getOTC()-getNPM();
        return(theval);
   }

   function getOFVI() {
        var theval = parseFloat(strip(document.calc.oldamt.value)) * Math.pow((getORC() + 1),getNPM());
        return(theval);
   }

   function getOFVA() {
        var theval = getOMP() * ((Math.pow((getORC()+1),getNPM())-1) / getORC());
        return(theval);
   }

   function getRB() {
        var theval = getOFVI()-getOFVA();
        return(theval);
   }

   function getNEWAMT() {
        var theval = getRB();
        return(theval);
   }

   function getNRC() {
        var theval = parseFloat(strip(document.calc.newrate.value))/1200;
        return(theval);
   }

   function getNTC() {
        var theval = parseFloat(document.calc.newterm.value)*12;
        return(theval);
   }

   function getNMP() {
        var theval = getNEWAMT() * getNRC() / (1 - 1 / Math.pow((getNRC()+1),getNTC()));
        return(theval);
   }

   function getMONTHSAVINGS() {
        var theval = getOMP()-getNMP();
        return(theval);
   }

   function getBREAKEVEN() {

        var theval = parseFloat(strip(document.calc.newfees.value))/getMONTHSAVINGS();





        return(theval);

   }

   function getOLDTOTINT() {

        var theval = getOMP()*getOTC()-parseFloat(strip(document.calc.oldamt.value));





        return(theval);

   }

   function getOIPD() {

        var theval = getOMP()*(getOTC()-getRNP())-parseFloat(strip(document.calc.oldamt.value))+getRB();





        return(theval);

   }

   function getOITBP() {

        var theval = getOLDTOTINT()-getOIPD();





        return(theval);

   }

   function getNEWTOTINT() {

        var theval = getNMP()*getNTC()-getNEWAMT();





        return(theval);

   }

   

   

   

   

   

///addl functions   

   function getNEWFEES() {

        var theval = strip(parseFloat(document.calc.newfees.value));





        return(theval);

   }

   function getOIPTD() {

        var theval = getOLDTOTINT()-getOIPD();





        return(theval);

   }



   function getADDITIONALINTEREST() {

        var theval = getNEWTOTINT()-getOIPTD();





        return(theval);

   }



function roundfloat(anum) {

    var snum = new String(anum);

        var dotidx = snum.indexOf(".");





        var newval;

        var newsval;

        var deci;

        if (dotidx > -1) {

                deci = snum.substring(dotidx,snum.length) * 100;

        deci = Math.round(deci);

        if (deci < 100) {

               newval = parseFloat(snum.substring(0,dotidx) + "." + deci);

            }else{

               newval = parseFloat(snum.substring(0,dotidx)) + 1;

                }

       //add superfluous zeros

       newsval = new String(newval);

       dotidx = newsval.indexOf(".");





       if (dotidx > -1) {

                //alert(newsval.substring(dotidx,newsval.length).length);

          if (newsval.substring(dotidx,newsval.length).length < 3) {

                        newsval += "0";

                        return(newsval);

          }

       }

       return(newsval);

    }else{

        snum += ".00";

        return(snum);

    }

}





function format(anum) {

  var negative = false;





  if (anum < 0) {

    anum = anum*-1;





    negative = true;





  }



  var thestring = new String(anum);

  var decindex = thestring.indexOf('.');





  var intstring = "";

  var decstring = "";

  var buildstring = "";

  var numstring = "";

  if (decindex > -1) {

        intstring = thestring.substring(0,decindex);

        decstring = thestring.substring(decindex,thestring.length);     

  }else{

        intstring = thestring;

  }

  var numlen = intstring.length;

  var curidx = numlen;

        if (numlen > 3) {

           while (curidx > -1) {

                        buildstring = intstring.charAt(curidx) + buildstring;

                        numstring = intstring.charAt(curidx) + numstring;

                        curidx--;

                        if (numstring.length == 3) {

                                if (curidx != -1) { 

                                buildstring = "," + buildstring;

                                numstring = "";

                            }     

                        }               

           }

           //prepend first digit

          // buildstring = intstring.charAt(0) + buildstring;

        }else{

          buildstring = intstring;

        }

  buildstring = "$" + buildstring + decstring;



  if (negative) {

     buildstring = "-" + buildstring;

  }





  return(buildstring);

}



function strip(astring) {

 var newstring = "";

 var achar = "XXX";

 for (i=0;i<astring.length;i++) {

    achar = astring.charAt(i,1);





    if (achar != "$" && achar != "," && achar != "%") {

        newstring += achar





    }

 }

 return (newstring);

}
thedate = new Date();

thismonth = thedate.getMonth() + 1;

thisyear = thedate.getYear();
if (thisyear < 1000) thisyear += 1900;
function calculate() {
        if (validate()) {
        //set each field like excel
document.calc.OMP.value = format(roundfloat(getOMP()));
document.calc.NMP.value = format(roundfloat(getNMP()));
//correct odd rounding from carried decimals
//document.calc.MONTHSAVINGS.value = format(roundfloat(getMONTHSAVINGS()));
var temp = format(parseFloat(strip(document.calc.OMP.value) - strip(document.calc.NMP.value)));
var anumstring = new String(temp);
var adecindex = anumstring.indexOf('.');
var monthsval = "";
  if (adecindex > -1) {
        var aintstring = anumstring.substring(0,adecindex);
        var adecstring = anumstring.substring(adecindex+1,anumstring.length);  
     if (adecstring.length > 2) {
		var tenths = anumstring.charAt(adecindex+1);
		var hundredths = anumstring.charAt(adecindex+2);
		var thousandths = anumstring.charAt(adecindex+3);  
		var decis = "";

          if (parseInt(thousandths) > 5) {

             decis = new String(tenths) + new String(hundredths);

          	 decis = parseInt(decis) + 1;

          	 decis = new String(decis);

          	 if (decis.length < 2) {

          	   decis = "0" + decis;

           }
          }else{
             decis = new String(tenths) + hundredths;
          }
        monthsval = aintstring + "." + decis;

     }else{

     	monthsval = anumstring + "0";
     }
 }else{

 	monthsval = anumstring;
 }
document.calc.MONTHSAVINGS.value = monthsval;
//breakout years
var yearamt = getBREAKEVEN();
var negative = false;
if (yearamt < 0) {
  negative = true;
  yearamt = yearamt * -1;
}
var yearp = 0;
var monthp = 0;
var y = 0;
while(y<yearamt) {
 monthp++;
 if (monthp == 12) {
        yearp++;
        monthp = 0;
 } 
 y++

}
var prettytime = "";

if (yearp > 0) {

  prettytime = yearp + " yrs";
}
if (monthp > 0) {
  prettytime = prettytime + " " + monthp + " mo";
}
if (negative) {
  prettytime = "-" + prettytime;
}
//prettytime = prettytime + yearamt;
//document.calc.BREAKEVEN.value = Math.round(getBREAKEVEN()) + " months";
document.calc.BREAKEVEN.value = prettytime;
//document.calc.ADDITIONALINTEREST.value = format(roundfloat(getADDITIONALINTEREST()));
document.calc.NPM.value =  getNPM();
document.calc.PAYSMADEZERO.value = 0;
document.calc.RNP.value =  getRNP();
document.calc.NTC.value =  getNTC();
// suggest a loan amount
document.calc.RB.value =  format(roundfloat(getRB()));
document.calc.OIPD.value =  format(roundfloat(getOIPD()));
document.calc.NIPDZERO.value = format("0.00");
document.calc.OIPTD.value =  format(roundfloat(getOIPTD()));
document.calc.NEWTOTINTcopy.value =  format(roundfloat(getNEWTOTINT()));
        }else{
document.calc.OMP.value = "--------";
document.calc.NMP.value = "--------";
document.calc.MONTHSAVINGS.value = "--------";
document.calc.BREAKEVEN.value = "--------";
//document.calc.ADDITIONALINTEREST.value = "--------";
document.calc.NPM.value =  "--------";
document.calc.PAYSMADEZERO.value = "--------";
document.calc.RNP.value = "--------";
document.calc.NTC.value = "--------";
document.calc.RB.value = "--------";
document.calc.OIPD.value = "--------";
document.calc.NIPDZERO.value = "--------";
document.calc.OIPTD.value = "--------";
document.calc.NEWTOTINTcopy.value = "--------";
       }
}
function basedoncurrent() {
  document.calc.RB.value =  format(roundfloat(getRB()));
}
function validate() {
        var returnval = true;
thevalue = parseInt(document.calc.oldyear.value);
document.calc.oldyear.value = thevalue;
if (thevalue < 1950 || thevalue > 3000) {
 alert("The year must be an integer between 1950 and 2003");
 document.calc.oldyear.focus();
 returnval = false;
}
//restrict input between 0 and 1,000,000,000
thevalue = parseFloat(strip(document.calc.oldamt.value));
if (thevalue < 0 || thevalue > 1000000000) {
 alert("The loan amount must be between 0 and 1,000,000,000");
 document.calc.oldamt.focus();
 returnval = false;
}
//restrict input to integer between 5 and 40
thevalue = parseInt(document.calc.oldterm.value);
document.calc.oldterm.value = thevalue;
if (thevalue < 5 || thevalue > 40) {
 alert("The old term must be an integer between 5 and 40");
 document.calc.oldterm.focus();

 returnval = false;
}
thevalue = parseInt(document.calc.newterm.value);
document.calc.newterm.value = thevalue;
if (thevalue < 5 || thevalue > 40) {

 alert("The new term must be an integer between 5 and 40");
 document.calc.newterm.focus();
 returnval = false;
}
//restrict input to decimal value between 2.000 and 20.000

thevalue = parseFloat(strip(document.calc.oldrate.value));

if (thevalue < 2 || thevalue > 20) {

 alert("The old rate must be a decimal value between 2.000 and 20.000");
 document.calc.oldrate.focus();
 returnval = false;

}
//restrict input to decimal value between 2.000 and 20.000
thevalue = parseFloat(document.calc.newrate.value);

if (thevalue < 2 || thevalue > 20) {
 alert("The new rate must be a decimal value between 2.000 and 20.000");
 document.calc.newrate.focus();
 returnval = false;
}
//restrict user input to between 0 and 1,000,000
thevalue = parseFloat(strip(document.calc.newfees.value));

if (thevalue < 0 || thevalue > 1000000) {
 alert("The new fees value must be between 0 and 1000000");
 document.calc.newfees.focus();
 returnval = false;
}
document.calc.newfees.value = format(thevalue);
if (returnval == false) {

   alert("Nothing Calculated!");    
}
return(returnval);
}