@vliv --
You didn't say which state you live in.
If you live in one state and work in another, then your resident state can tax ALL your income, regardless of where you earn it. A non-resident state can tax income that you earn by working within its borders. As @Hal_Al indicated, a non-resident state might use your gross overall income to determine your tax rate, but it will actually tax only your income from that state.
Your resident state will grant you a credit for taxes you pay to a non-resident state on the income taxed by both, so in the end you won't be double-taxed.
If you literally move from one state to another during the tax year, then you file a part-year resident return in each of the two states and allocate your income accordingly.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
