The window.requestIdleCallback() method queues a function to be called during a browser's idle periods. This enables developers to perform background and low priority work on the main event loop, without impacting latency-critical events such as animation and input response. Functions are generally called in first-in-first-out order unless the function's timeout is reached before the browser calls it.
WindowTimers is a mixin used to provide utility methods which set and clear timers. No objects of this type exist; instead, its methods are available on Window for the standard browsing scope, or on WorkerGlobalScope for workers.