Power Efficient Callback Patterns

In one or more embodiments, an application program interface (API) is provided and enables an entity, such as an application, script, or other computing object to register to receive callbacks immediately and, without specifying a time constraint. In this approach, the API does not rely on a timer, such as a system timer. Rather, a non-timer based queue, such as a message queue-type approach is utilized. Specifically, callbacks that are registered through this API can be placed on the message queue and work associated with the registered callback can be performed through the normal course of processing messages and events in the message queue. Over time, such results in a callback pattern that allows an associated web browser and applications such as web applications to remain responsive, while increasing performance and power efficiencies.