AnimationTimeline

Web animations web-animations

Baseline: Widely available on the web, in every major browser since Sep 2020, and long enough to count on (since Mar 2023).

niso: Partial 91%. 3301 of 3589 subtests pass, by system: Linux 91%, macOS 91%. Engines: QuickJS, the engine niso's WPT run uses; Node and Porffor have no recorded run. WPT results recorded at f3b4fa8, 2026-11-10; web-features 3.45.0. WPT tests · niso's support · Animation, AnimationEffect, AnimationPlaybackEvent, AnimationTimeline

AnimationTimeline is an interface in idl/web-animations.webidl, exposed in Window. What it does is on MDN; this page says what niso has of it.

Status

The web features its members belong to, each with its Baseline status on the web and how much of the feature’s WPT suite passes in niso (see Web platform support).

Feature	On the web	In niso	Members
Web animations	Widely available	Partial 91% 3301 of 3589 subtests pass	2

Members

currentTime

attribute

[NisoGlue] readonly attribute double? currentTime;

time()

operation not in JS

[NisoInternal] unrestricted double time();

int32_t niso_animation_timeline_time(niso_dom* dom, niso_handle self, double* out);

Not in niso yet

Members the web has, by the BCD keys web-features 3.45.0 lists, that idl/ doesn’t declare. The list is partial: web-features lists only the keys it maps to a feature.

• duration (Web animations)