This note considers the issue of global asymptotic stabilization for a class of nonlinear systems with unknown time-varying delays and control gain using a dynamic event-triggered (DET) output feedback scheme. In the context of unknown time-varying delays and control gain, nonsmooth control law and some extra redundant terms will be encountered in the design of DET controller, which would bring substantial challenges to the achievement of event-triggered stabilization. Specifically, two dynamic gains and a modified Lyapunov-Krasovskii functional are first presented, which makes the effects of time-varying delays and control gain be conquered. Then, a DET mechanism utilizing the dynamic gain is given to reduce the amounts of event transmissions and dynamically compensate the triggering error. By virtue of the designed strategy, a new DET output feedback controller is developed, which renders the closed-loop system globally asymptotically stable. Meanwhile, it is proved that the Zeno behavior does not happen. Finally, in order to demonstrate the feasibility of the proposed scheme, corresponding examples are provided.