Animation 曲线运动测试

测试实例如下：

<div class="outer">
  <div class="ball"></div>
</div>

.outer {
  width: 1000px;
  height: 500px;
  background: pink;
  position: relative;
}
.ball {
  position: absolute;
  width: 50px;
  height: 50px;
  background: aqua;
  animation: move1 1s 0s 1 linear, move2 1s 0s 1 cubic-bezier(1,0,1,1), move3 1s 1s 1 linear, move4 1s 1s 1 cubic-bezier(0,1,1,1);
  animation-fill-mode: forwards;
}
@-webkit-keyframes move1 {
  0% {
    top: 0;
  }
  100% {
    top: 200px;
  }
}
@-webkit-keyframes move2 {
  0% {
    left: 0;
  }
  100% {
    left: 200px;
  }
}
@-webkit-keyframes move3 {
  0% {
    top: 200px;
  }
  100% {
    top: 0;
  }
}
@-webkit-keyframes move4 {
  0% {
    left: 200px;
  }
  100% {
    left: 400px;
  }
}