<!doctype html>
<html>
<head>
<script>
function start () {
  const keyframe = new KeyframeEffect(undefined, {});
  const animation = new Animation(keyframe, undefined);
  // Make animation run backwards...
  animation.playbackRate = -100;
  // But then set the current time to the future so it becomes "current"...
  animation.currentTime = 2055;
  // After updating the playback rate to zero, however, it should no longer
  // be "current" (and this takes effect immediately because |animation| is
  // paused)...
  animation.updatePlaybackRate(0);
  // Now update the target and hope nothing goes wrong...
  keyframe.target = div;
}

document.addEventListener('DOMContentLoaded', start)
</script>
</head>
<div id=div></div>
</html>
