his was very helpful as I am just learning I weas curious as to how to create and reference js files so I didnt have to have the scripts in my HTML pages

How can you get the value from a JS function that is in a seperate file to an inputbox on another page?

Code:

if (!Array.prototype.reduce) {
Array.prototype.reduce = function reduce(accumulator){
if (this===null || this===undefined) throw new TypeError("Object is null or undefined");
var i = 0, l = this.length >> 0, curr;
if(typeof accumulator !== "function") // ES5 : "If IsCallable(callbackfn) is false, throw a TypeError exception."
throw new TypeError("First argument is not callable");
if(arguments.length < 2) {
if (l === 0) throw new TypeError("Array length is 0 and no second argument");
curr = this[0];
i = 1; // start accumulating at the second element
}
else
curr = arguments[1];
while (i < l) {
if(i in this) curr = accumulator.call(undefined, curr, this[i], i, this);
++i;
}
return curr;
};
}
function formatDollar(num) {
var p = num.toFixed(2).split(".");
return "$" + p[0].split("").reverse().reduce(function(acc, num, i, orig) {
return num + (i && !(i % 3) ? "," : "") + acc;
}, "") + "." + p[1];
}
function centNotation(value)
{
dollars = Math.floor(value); // chop floating point portion
cents = Math.floor((value % 1) * 100); // and chop everything else
if (cents < 10) cents = "" + cents + "0";
return(dollars + "." + cents);
}
function validInt(value)
{
for (var i=0; i < value.length; i++) {
var c = value.charAt(i);
if ((c < '0' || c > '9') && c != '.') {
alert("There's a problem: all values herein must " +
"be numbers only, and " + value + " has an unacceptable character " +
"'" + c + "'");
return(false);
}
}
return(true);
}
function myPaymentCalc()
{
var interestRate = document.debtcalc.interest.value,
monthlyPayment = document.debtcalc.monthlypayment.value,
principal = document.debtcalc.principal.value,
accumulatingInterest = 1;
if (! validInt(interestRate) || ! validInt(monthlyPayment) ||
! validInt(principal))
return(false);
if (interestRate == 0 || monthlyPayment == 0 || principal == 0) {
alert("You need to specify your monthly payment, credit card " +
"interest rate and current debt amount before I can calculate " +
"how long it'll take for you to pay off your debt.");
return(false);
}
interestRate = (interestRate > 1)? interestRate / 100.0 : interestRate;
monthlyInterestRate = interestRate / 12;
if (principal * monthlyInterestRate > monthlyPayment) {
monthlyrate = "$" + centNotation(principal * monthlyInterestRate);
permonthPayment = "$" + centNotation(monthlyPayment);
alert("You've got a fundamental problem: your monthly payment of " +
permonthPayment + " is less than the interest added each month " +
"(which is " + monthlyrate + ") and you will never " +
"pay off this debt. It might be a good time to call your creditors.");
return(false);
}
interimVal1 = monthlyPayment - (monthlyInterestRate * principal)
numberOfPayments = (Math.log(monthlyPayment) - Math.log(interimVal1)) /
Math.log(1+monthlyInterestRate);
numberOfPayments = Math.ceil(numberOfPayments);
interimVal2 = Math.pow((monthlyInterestRate+1), (numberOfPayments-1));
remaining = (principal * interimVal2) -
(monthlyPayment/monthlyInterestRate) * (interimVal2 - 1);
totalPayment = monthlyPayment *(numberOfPayments-1) + remaining;
payments = numberOfPayments;
<!-- totalpayment = "$" + centNotation(totalPayment);-->
<!-- interestPaid = "$" + centNotation(totalPayment-principal);-->
totalpayment = formatDollar(totalPayment);
interestPaid = formatDollar(totalPayment-principal);
alert("Given these figures, you'll end up having " + payments +
" payments and pay a total of " + totalpayment + ", of which " +
interestPaid + " is interest.");
document.debtcalc.numberofpayments.value = payments; *these represent inputboxes that got populated*
document.debtcalc.totalpayments.value = totalpayment; *They dont get populated if I place this script in a seperate file*
document.debtcalc.intpmt.value = interestPaid; *Everything else works so I am referencing it correctly just not populating the HTML boxes properly*
}
</script>

If this script is in my HTML page it works fine, but if I place it in a seperate file and reference it from my HTML page then the last 3 lines do NOT work

I am sure I need to reference them differently but not sure how