Be aware that that NJ will credit you for the Philly Wage Tax only to the extent of what would have been the NJ tax on those same wages. In other words, if the Philly Wage Tax is a higher percent than your NJ income tax, you won't receive a full credit.
And, if you have other, non-wage NJ income, it may be subject to NJ tax.
Credit for Income Taxes Paid to Other Jurisdictions (Wage Income) (state.nj.us) at p. 10.
