.xxx {
  animation-play-state: paused; 
  //该属性一旦被添加,CSS动画会立即暂停,并且保持于当前帧
}

.xxx {
  animation-play-state: running;
  //该属性一旦被添加,CSS动画会立即从当前帧开始运作;
}

animation-play-state:paused

//i等于1时媒体播放并且音符飘动,i等于0时媒体暂停音符暂停.
            if (i == 1) {
                right.style.animationPlayState = "paused"
                audio.pause();
                i = 0;
            } else {
                right.style.animationPlayState = "running";
                audio.play();
                i = 1;
            }