gistfile1.dart

class MyAnimation extends LoopedAnimation {

  const DURATION = 1000;
  final dom.Element element;
  final AnimationLoop animationLoop;

  MyAnimation(this.element, this.animationLoop) {
    animationLoop.play(this);
  }

  bool update(num timeCount) {
    //render the animation styling here...
    //element.style.prop = '...';

    //whether to stop the animation or not
    return timeCount < DURATION;
  }
}