Tax calculator in javascript

How do I split the result for the income tax brackets to auto display the right tax due when the gross pay affected is in a particular tax bracket.

Income Tax Bands    Tax Rates     Tax Due
3,300.00 and Below         0%        0
3,300.01 – 4,100.00        25%       0
4,100.01 – 6,200.00        30%       0
6,200.00 and Above         37.5%     0