小编Min*_*Min的帖子

div {
  border: 3px dashed #ccc;
  padding: 20px;
}

div::before { content: attr(class); }

.grandparent { overflow: auto; }
.parent { position: relative; }
.child { position: absolute; height: 60px; background: black; color: white; }

<div class="grandparent">
  <div class="parent">
    <div class="child"></div>
  </div>
</div>