Make Absolute Positioned Div Expand Parent Div Height

Make absolute positioned div expand parent div height

You answered the question by yourself: "I know that absolute positioned elements are removed from the flow, thus ignored by other elements." So you can't set the parents height according to an absolutely positioned element.

You either use fixed heights or you need to involve JS.

How to set parent div's height as child div with position: absolute

I don't think this is possible with CSS while keeping the children absolutely positioned.

Absolutely positioned elements are completely removed from the document flow, and thus their dimensions cannot alter the dimensions of their parents.

If you really had to achieve this affect while keeping the children as position: absolute, you could do so with JavaScript by finding the height of the absolutely positioned children after they have rendered, and using that to set the height of the parent.

var content=document.querySelector('.content');var container=document.querySelector('.container');
content.style.height=container.offsetHeight + 'px';

*{box-sizing:border-box;}
.content {  width: 100%;  max-width: 1160px;  margin: 0 auto;  /*padding: 120px 0;*//*Padding removed for example*/   border:5px solid green;}.container{  position: absolute;  overflow: hidden;  width: 100%;  border:2px solid red;  height:652px;}

<div class="content">  <div class="container">    some other elements whose height is 652px...  </div></div>

Make parent div height according to children absolute div

Use display:grid and make both elements on the same area and you will have the overlapping effect without position:absolute

.main {
  position: absolute;
  z-index: 500;
  left: 56px;
  display: block;
}

.parent {
  position: relative;
  margin: 10px;
  display:grid; /* here */
  align-items:start; /* disable stretch alignment */
}

.parent>* {
  grid-area:1/1; /* here */
}

.parent>*:nth-of-type(1) {
  z-index: 10;
}

.parent>*:nth-of-type(2) {
  margin-top:1.4rem; /* you can now use margin instead of translate */
  transform: scale(.95);
  z-index: 9;
}

<div class="main">
  <div id="parent1" class="parent">
    <div class="child" style="background-color:blue;"><br>Child1</div>
    <div class="child" style="background-color:red;"><br><br><br>Child2</div>
  </div>
  <div id="parent2" class="parent">
    <div class="child" style="background-color:green;"><br>Child1</div>
    <div class="child" style="background-color:yellow;"><br>Child2</div>
  </div>
</div>

Position: absolute and parent height?

2022 UPDATE. This answer is nearly 10 years old. When it was written we didn't have layout technologies like Flex or Grid available (they were dark, hacky/fun times).

Thankfully things have massively improved. Jöcker's answer shows you how to achieve this layout with Grid. If you can live with not supporting legacy browsers, do that instead!

Original Answer

If I understand what you're trying to do correctly, then I don't think this is possible with CSS while keeping the children absolutely positioned.

Absolutely positioned elements are completely removed from the document flow, and thus their dimensions cannot alter the dimensions of their parents.

If you really had to achieve this affect while keeping the children as position: absolute, you could do so with JavaScript by finding the height of the absolutely positioned children after they have rendered, and using that to set the height of the parent.

Alternatively, just use float: left/float:right and margins to get the same positioning effect while keeping the children in the document flow, you can then use overflow: hidden on the parent (or any other clearfix technique) to cause its height to expand to that of its children.

article {
    position: relative;
    overflow: hidden;
}

.one {
    position: relative;
    float: left;
    margin-top: 10px;
    margin-left: 10px;
    background: red;
    width: 30px;
    height: 30px;
}

.two {
    position: relative;
    float: right;
    margin-top: 10px;
    margin-right: 10px;
    background: blue;
    width: 30px;
    height: 30px;
}

Make Absolute Positioned Div Expand Parent Div Height