Calculating future value with compound interest with JavaScript

Question

I\'m trying to work on a script where the user inserts a monthly income and gets the future value with compound interest after 30 years. As it is now, I\'ve assigned some values

Answer 1

function FVcalc(PresentAmount,InterestRate,NumberOfYears) {
    var timescompound = 1;
    var AnnualInterestRate = (InterestRate/100)/timescompound;
    var Years= NumberOfYears

    var Periods=timescompound*Years;
    var NumPayments=Periods;
    var Prin=PresentAmount;

    MonthPayment=Math.floor((Prin)*(Math.pow((1+AnnualInterestRate),(Periods)))*100)/100;
    FVFactor=(Math.pow((1+AnnualInterestRate),(Periods)))
    return MonthPayment
}

http://www.uic.edu/classes/actg/actg500/pfvatutor.htm