When the z-index property is not specified on any element, elements are stacked in the following order (from bottom to top):

  1. The background and borders of the root element
  2. Descendant non-positioned blocks, in order of appearance in the HTML
  3. Descendant positioned elements, in order of appearance in the HTML

In the example below, elements #1 through #4 are positioned elements. Element #5 is static, and so is drawn below the other four elements, even though it comes later in the HTML markup.

Source code for the example

HTML

<div id="abs1" class="absolute">
  <b>DIV #1</b><br />position: absolute;</div>
<div id="rel1" class="relative">
  <b>DIV #2</b><br />position: relative;</div>
<div id="rel2" class="relative">
  <b>DIV #3</b><br />position: relative;</div>
<div id="abs2" class="absolute">
  <b>DIV #4</b><br />position: absolute;</div>
<div id="sta1" class="static">
  <b>DIV #5</b><br />position: static;</div>

CSS

b {
  font-family: sans-serif;
}

div {
  padding: 10px;
  border: 1px dashed;
  text-align: center;
}

.static {
  position: static;
  height: 80px;
  background-color: #ffc;
  border-color: #996;
}

.absolute {
  position: absolute;
  width: 150px;
  height: 350px;
  background-color: #fdd;
  border-color: #900;
  opacity: 0.7;
}

.relative {
  position: relative;
  height: 80px;
  background-color: #cfc;
  border-color: #696;
  opacity: 0.7;
}

#abs1 {
  top: 10px;
  left: 10px;
}

#rel1 {
  top: 30px;
  margin: 0px 50px 0px 50px;
}

#rel2 {
  top: 15px;
  left: 20px;
  margin: 0px 50px 0px 50px;
}

#abs2 {
  top: 10px;
  right: 10px;
}

#sta1 {
  background-color: #ffc;
  margin: 0px 50px 0px 50px;
}

See also

Original Document Information

Document Tags and Contributors

 Last updated by: mfluehr,