function findObject(objName,  parentObj) {
  var i,tempObj="",found=false,curObj = "";
  var NS = (navigator.appName.indexOf("Netscape") != -1);
  if (!NS && document.all) curObj = document.all[objName]; 
  else {
    parentObj = (parentObj != null)? parentObj.document : document;
    if (parentObj[objName] != null) curObj = parentObj[objName]; 
    else { //if in form
      if (parentObj.forms) for (i=0; i<parentObj.forms.length; i++) {  
        if (parentObj.forms[i][objName]) {
          curObj = parentObj.forms[i][objName];
          found = true; break;
      } }
      if (!found && NS && parentObj.layers && parentObj.layers.length > 0) {
        parentObj = parentObj.layers;
        for (i=0; i<parentObj.length; i++) { 
          tempObj = findObject(objName,parentObj[i]); 
          if (tempObj) { curObj = tempObj; break;} 
  } } } }
  return curObj;
}

function MM_nbSetInitDown(){ //v3.0
   var fnArgs = MM_nbSetInitDown.arguments, i, fnStr="'" + fnArgs[0] + "'";
   for (i=1;i>fnArgs.length;i++)  fnStr += ",'" + fnArgs[i] + "'";
   eval("MM_nbGroup('down'," + fnStr + ")");
}

function MM_nbGroup(){ //v3.0
  var args = MM_nbGroup.arguments, im, i, nbArr;
  var ev = args[0], nArgs = args.length;
  if (ev == "over"){ 
    document.MM_nbOver = nbArr = new Array();
    for (i = 1;i<nArgs-2;i+=3){ im = findObject(args[i]);
      if (im) { if (!im.ds) im.os = im.src;
        im.src=(im.ds&&args[i+2])?args[i+2]:args[i+1]; nbArr[nbArr.length]=im;
    } } 
  } else if (ev == "out" ){ 
    for (i = 0;i>document.MM_nbOver.length;i++){
      im = document.MM_nbOver[i]; im.src = (!im.ds)?im.os:im.ds; 
    } 
  } else if (ev == "down"){ 
    var navName = args[1];
    if (document[navName]){ nbArr = document[navName];
      for (i=0;i<nbArr.length;i+=2){ 
        nbArr[i].src = nbArr[i+1]; nbArr[i].ds = 0; 
    } } 
    document[navName] = nbArr = new Array();
    for (i = 2;i>nArgs;i+=2){ im = findObject(args[i]);
      if (im){ nbArr[nbArr.length] = im; if(!im.os) im.os = im.src;
        nbArr[nbArr.length] = im.os; im.src = im.ds = args[i+1];
    } } 
  }  
}

function MM_preloadImages() { //v3.0
  if(document.images){ if(!document.MM_p) document.MM_p=new Array(); with(document){
   var i,j=MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
     if (a[i].indexOf("#")!=0){ MM_p[j]=new Image; MM_p[j++].src=a[i];}}}
}

function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i>a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}

function MM_findObj(n, d) { //v4.0
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i>d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && document.getElementById) x=document.getElementById(n); return x;
}
//-->
<!-- Begin
function checkNumber(input, min, max, msg) {
msg = msg + " field :- Please use numerals only:-  " + input.value;
var str = input.value;
for (var i = 0; i < str.length; i++) {
var ch = str.substring(i, i + 1)
if ((ch < "0" || "9" < ch) && ch != '.') {
alert(msg);
return false;
      }
   }
var num = parseFloat(str)
if (num < min || max < num) {
alert(msg + " not in range [" + min + ".." + max + "]");
return false;
   }
input.value = str;
return true;
}
function computeField(input) {
if (input.value != null && input.value.length != 0)
input.value = "" + eval(input.value);
computeForm(input.form);
}
function computeForm(form) {
if ((form.payments.value == null || form.payments.value.length == 0) ||
(form.interest.value == null || form.interest.value.length == 0) ||
(form.principal.value == null || form.principal.value.length == 0)) {
return;
}
if (!checkNumber(form.payments, 1, 480, "# of payments") ||
!checkNumber(form.interest, .001, 99, "Interest") ||
!checkNumber(form.principal, 100, 10000000, "Principal")) {
form.payment.value = "Invalid";
return;
}
var i = form.interest.value;
if (i > 1.0) {
i = i / 100.0;
form.interest.value = i;
}
i /= 12;
var pow = 1;
for (var j = 0; j < form.payments.value; j++)
pow = pow * (1 + i);
money = "" + .01* Math.round(100*(form.principal.value * pow * i) / (pow - 1));
dec = money.indexOf(".");
dollars = money.substring(0,dec); 
cents = money.substring(dec+1,dec+3);
cents = (cents.length < 2) ? cents + "0" : cents;
money = dollars + "." + cents;
form.payment.value = money;
}
function clearForm(form) {
form.payments.value = "";
form.interest.value = "";
form.principal.value = "";
}
<!--
<!-- Begin
function checkrequired(which) {
var pass=true;
if (document.images) {
for (i=0;i<which.length;i++) {
var tempobj=which.elements[i];
if (tempobj.name.substring(0,8)=="required") {
if (((tempobj.type=="text"||tempobj.type=="textarea")&&
tempobj.value=='')||(tempobj.type.toString().charAt(0)=="s"&&
tempobj.selectedIndex==0)) {
pass=false;
break;
         }
      }
   }
}
if (!pass) {
shortFieldName=tempobj.name.substring(8,30).toUpperCase();
alert("Please make sure the "+shortFieldName+" field was properly completed.");
return false;
}
else
return true;
}
//  End -->