  The frequency-dependent scaling of the dispersive and dissipative parts of
the alternating susceptibility is studied for spin glasses at criticality. An
extension of the usual $\omega t$-scaling is proposed. Simulational data from
the three-dimensional Ising spin glass agree with this new scaling form and
moreover reproduce well the scaling functions explicitly calculated for systems
satisfying local scale-invariance. There is also a qualitative agreement with
existing experimental data.
