如何实现div与另一个div的重叠？

Question

我如何实现一个<div>重叠，以便div #inner-block我们在前台？

​

#block-1 {
  position: absolute;
  width: 200px;
  height: 200px;
  top: 10px;
  left: 10px;
  background-color: #999;
  z-index: 1;
}

#inner-block {
  position: relative;
  width: 100px;
  height: 100px;
  margin: 20px;
  background-color: #777;
  z-index: 100;
}

#block-2 {
  position: absolute;
  width: 200px;
  height: 200px;
  top: 60px;
  left: 60px;
  background-color: #666;
  z-index: 2;
}

<div id="block-1">
  <div id="inner-block"></div>
</div>
<div id="block-2"></div>

​

Answer 1

一个简单的解决方案是更新HTML，如下所示：

<div id="block-1">
  <div id="inner-block"></div></div>
  <div id="block-2">
</div>

这是因为它确保block-2和inner-block的排序相对于公共父级；block-1。

​

#block-1
{
  position: absolute;
  width: 200px;
  height: 200px;
  top: 10px;
  left: 10px;
  background-color: #999;
  z-index: 1;
}
#inner-block
{
  position: relative;
  width: 100px;
  height: 100px;
  margin: 20px;
  background-color: #777;
  z-index: 100;
}
#block-2
{
  position: absolute;
  width: 200px;
  height: 200px;
  top: 60px;
  left: 60px;
  background-color: #666;
  z-index: 2;
}

<div id="block-1">
  <div id="inner-block"></div>
  <div id="block-2"></div>
</div>

​

希望这能有所帮助！