yellow;
    position: absolute;
    top: 50px;
  }

  .sticky {
    position: absolute;
    background: purple;
    width: 50px;
    height: 50px;
    top: 200px;
    z-index: 1;
  }
  </style>
  <script>
  function runTest() {
    document.getElementById("scroll2").scrollTop = 50;
  }
  </script>

  <body onload="runTest();">
    <div class="scroll">
      <div class="sticky"></div>
      <div class="block"></div>
    </div>

    <div class="scroll" id="scroll2">
      <div class="sticky"></div>
      <div