//DO NOT REMOVE THIS COPYWRITE INFO!
//Debt Investment Calculator
//By Daniel C. Peterson
//Web Winder Website Services, 1997-2006  All Rights Reserved.
//Distribution, editing or reselling of this script is strictyly prohibited
//without expressed written permission from Daniel C. Peterson.
//For commercial grade (professional) versions of this and many other
//calculators, visit http://www.webwinder.com.

function computeForm(form) {

var i = form.interest.value;

    if (i >= 1.0) {

        i = i / 100.0;

        form.interest.value = i;

    }

     i /= 12;


   var prin1 = eval(form.principal.value);

   var prin2 = eval(form.principal.value);

   var pmt1 = form.origPmt.value;

   var pmt2 = eval(form.origPmt.value) + eval(form.pmtAdd.value);

   var prinPort1 = 0;

   var prinPort2 = 0;

   var intPort1 = 0;

   var intPort2 = 0;

   var count1 = 0;

   var count2 = 0;

  var accumInt1 = 0;
  var accumInt2 = 0;
    
   while(prin1 > 0) {
                    intPort1 = eval(i * prin1);
                    accumInt1 = eval(accumInt1) + eval(intPort1);
                    prinPort1 = eval(pmt1 - intPort1);
                    prin1 = eval(prin1 - prinPort1);
                    count1 = count1 + 1
                    if(count1 > 600) { break; } else { continue;}
                    }

   while(prin2 > 0) {
                    intPort2 = eval(i * prin2);
                    accumInt2 = eval(accumInt2) + eval(intPort2);
                    prinPort2 = eval(pmt2 - intPort2);
                    prin2 = eval(prin2 - prinPort2);
                    count2 = count2 + 1
                    if(count2 > 600) { break; } else { continue;}
                    }

      form.intSave.value = eval(accumInt1) - eval(accumInt2);
      form.roi.value = (form.intSave.value / (count2 * form.pmtAdd.value)) / (count2 / 12);

     var timSave = eval(count1) - eval(count2);

      form.results.value = ("If you add $" + form.pmtAdd.value + " to your monthly payment, you will pay off this debt in " + count2 + " payments instead of " + count1 + ", and you will save $" + parseInt(form.intSave.value,10) + " in interest charges.  This savings translates into a guaranteed, tax-free, average annual return of " + parseInt(form.roi.value * 100,10) + "%.  And that's not even considering the emotional returns you'll get when you pay off this debt " + timSave + "-months (" + parseInt(timSave /12,10) + " years, " + (timSave %12) + " months) ahead of schedule!");
}



function clearForm(form)

{

    form.principal.value = "";

    form.interest.value = "";

    form.origPmt.value = "";

    form.pmtAdd.value = "";

    form.intSave.value = "";

    form.roi.value = "";

    form.results.value = "";
}