渐进伸缩的样式

css

<button>test<button>

css

.asyncButton:after {
  content: '';
  background-color: rgba(112, 76, 182, 0.15);
  display: block;
  position: absolute;
  width: 100%;
  height: 100%;
  left: 0;
  top: 0;
  opacity: 0;
  transition: width 1s linear, opacity 0.5s ease 1s;
}

.asyncButton:active:after {
  width: 0%;
  opacity: 1;
  transition: 0s;
}