Go to a different applet:
I made this specifically as a demo for lab 11 in the entry-level programming class at BYU. The basis of it is you enter an interest rate (by percent) in the one field and an initial credit card balance. When you hit the button, a month goes by- you pay a minimum payment of either $20 or 2% of the current balance (whichever is greater), and you get charged the interest. A good way to learn to pay your credit card bills ASAP.
Report bugs and give suggestions here.
These applets were developed by Matthew Reeder. Please get my permission before using these applets on your own site.
(And trust me, it will be easier if I help you use them :-p)