var animationProp = CSSKeyframer.animationProp.js; var keyframer = new CSSKeyframer(); keyframer.register("spin", [ { transform: "rotate(0deg)", borderRadius: "0" }, { transform: "rotate(72deg)", borderRadius: "50%" }, { transform: "rotate(144deg)", borderRadius: "0" }, { transform: "rotate(216deg)", borderRadius: "50%" }, { transform: "rotate(360deg)", borderRadius: "0" } ]); keyframer.register("