JavaScript Period Rate Calculator 
This calculator will work out the period rate from an annual effective rate (such as an APR). Enter the frequency as the number of periods in a year (for example, 12 for monthly charging periods). To use the calculator, fill in the figures in the boxes marked '*' below and click on the 'Calculate' button to display the result in the final box. Click on the 'Reset' button to clear the calculator for a new calculation. Coded in JavaScript and HTML by Brian Stewart, v1.1 December 2001
