Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The firstUIEventTimestamp read-only property of the PerformanceLongAnimationFrameTiming interface returns a DOMHighResTimeStamp indicating the time of the first UI event — such as a mouse or keyboard event — to be processed during the current animation frame. Note this timestamp can be before the start of this animation frame if there was a delay between the event happening and it being processed.
See Long animation frame timing for examples related to the Long Animation Frames API.