This paper proposes a novel approach to input-to-state stabilization and integral input-to-state stabilization problems for nonlinear systems based on the concept of state-dependent scaling design. Both state-feedback and output-feedback controllers are constructed in a unified way. The method provides global solutions whenever the system is in the strict-feedback or output-feedback form. The paper allows the system to have structured, static and dynamic uncertainties. An advanced recursive procedure of observer design is the key to input-to-state stabilization by output feedback.