问如何将多个div层叠在一起，并在用户滚动每个div时向上移动以显示其后面的div？

EN

$(window).scroll(function (e) {
  var scroll = $(window).scrollTop();

  if (scroll > 120) {
    $(".div-1").slideUp();
  }

  if (scroll > 240) {
    $(".div-2").slideUp();
  }
});

section {
  height: 900px;
}

div {
  position: absolute;
  left: 0;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  width: 10rem;
  height: 900px;
  font-size: 2rem;
}

.div-1 { background: #faa; }
.div-2 { background: #aff; }
.div-3 { background: #ffa; }

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<section>
  <div class="div-3">3</div>
  <div class="div-2">2</div>
  <div class="div-1">1</div>
</section>