ReadonlycurrentThe currentTime read-only property of the Web Animations API's AnimationTimeline interface returns the timeline's current time in milliseconds, or null if the timeline is inactive.
ReadonlydurationThe duration read-only property of the Web Animations API's AnimationTimeline interface returns the maximum value for this timeline or null.
The
AnimationTimelineinterface of the Web Animations API represents the timeline of an animation. This interface exists to define timeline features, inherited by other timeline types:MDN Reference