  In this paper, the purity of quantum states is applied to probe chaotic
dissipative dynamics. To achieve this goal, a comparative analysis of regular
and chaotic regimes of nonlinear dissipative oscillator (NDO) are performed on
the base of excitation number and the purity of oscillatory states. While the
chaotic regime is identified in our semiclassical approach by means of strange
attractors in Poincar\'e section and with the Lyapunov exponent, the state in
the quantum regime is treated via the Wigner function. Specifically,
interesting quantum purity effects that accompany the chaotic dynamics are
elucidated in this paper for NDO system driven by either: (i) a time-modulated
field, or (ii) a sequence of pulses with Gaussian time-dependent envelopes.
