JavaScript Compound Interest Calculator

My friend Mark Pollard asked me "How rich would Jesus be today, if he was an investment banker?", so I wrote this JavaScript program to calculate a compounded annually accredited interested rate over any given period of time. The program is year 2000 compliant, works with dates BC (just use negative numbers), and will go many millions of years into the future if needs be. You'll need a suitably fast computer to go this far ahead however. But actually... how rich was jesus anyhow?

This rich by 2000 at 2%: $155,504,639,961,153,000! I've checked the accuracy with this Excel file but its got an obvious rounding error and of course the fact that most investments would compound monthly not yearly etc.

When the screen is RED Javascript is doing calculations, when it is GREEN CPU is idling.

Amount Invested
Starting Year
Ending Year
Interest Rate %