CSSKeyframeRule

Animations (CSS) animations-css

Baseline: Widely available on the web, in every major browser since Sep 2015, and long enough to count on (since Mar 2018).

niso: Partial 56%. 649 of 1148 subtests pass, by system: Linux 56%, macOS 56%. 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 · CSSKeyframeRule, CSSKeyframesRule

CSSKeyframeRule is an interface in idl/cssom.webidl, inheriting CSSRule, 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
Animations (CSS)	Widely available	Partial 56% 649 of 1148 subtests pass	3

Members

keyText

attribute

readonly attribute DOMString keyText;

int32_t niso_css_keyframe_rule_get_key_text(niso_dom* dom, niso_handle self, niso_str* out);

style

attribute

[SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;

int32_t niso_css_keyframe_rule_get_style(niso_dom* dom, niso_handle self, niso_handle* out);