如何在jQuery中关注滚动条时禁用可拖动的div

<div id="draggable" class="draggable">可拖动的div</div>

.draggable {
  position: absolute;
  top: 50px;
  left: 50px;
  width: 200px;
  height: 200px;
  background-color: #ccc;
  cursor: move;
}

.disabled {
  pointer-events: none;
  opacity: 0.5;
}

$(window).scroll(function() {
  var scrollTop = $(this).scrollTop();
  var draggable = $("#draggable");

  if (scrollTop > 100) {
    draggable.addClass("disabled");
  } else {
    draggable.removeClass("disabled");
  }
});