Make absolute child full length inside a scrollable container

Question

With the following HTML and CSS

.container {
  position: relative;
  border: solid 1px red;
  height: 256px;
  width: 256px;
  overflow: auto;
}
.full-height {
  position: absolute;
  top: 0;
  left: 0;
  right: 128px;
  bottom: 0;
  background: blue;
}

<div class="container">
  <div class="full-height">
  </div>
</div>

The inner div takes up the full head of the container as desired. If I now add some other, flow, content to the container such as:

.container {
  position: relative;
  border: solid 1px red;
  height: 256px;
  width: 256px;
  overflow: auto;
}
.full-height {
  position: absolute;
  top: 0;
  left: 0;
  right: 128px;
  bottom: 0;
  background: blue;
}

<div class="container">
  <div class="full-height">
</div>

  Lorem ipsum dolor sit amet, consectetur adipisicing elit. Aspernatur mollitia maxime facere quae cumque perferendis cum atque quia repellendus rerum eaque quod quibusdam incidunt blanditiis possimus temporibus reiciendis deserunt sequi eveniet necessitatibus
  maiores quas assumenda voluptate qui odio laboriosam totam repudiandae? Doloremque dignissimos voluptatibus eveniet rem quasi minus ex cumque esse culpa cupiditate cum architecto! Facilis deleniti unde suscipit minima obcaecati vero ea soluta odio cupiditate
  placeat vitae nesciunt quis alias dolorum nemo sint facere. Deleniti itaque incidunt eligendi qui nemo corporis ducimus beatae consequatur est iusto dolorum consequuntur vero debitis saepe voluptatem impedit sint ea numquam quia voluptate quidem.
</div>

Then the container scrolls as desired, however the absolutely positioned element is no longer anchored to the bottom of the container but stops at the initial view-able bottom of the container.

Is there any way of having the absolutely positioned element be the complete scroll height of its container without using JS?

Answer 1

You need to wrap the text in a div element and include the absolutely positioned element inside of it.

<div class="container">
    <div class="inner">
        <div class="full-height"></div>
        [Your text here]
    </div>
</div>

Css:

.inner: { position: relative; height: auto; }
.full-height: { height: 100%; }

Setting the inner div's position to relative makes the absolutely position elements inside of it base their position and height on it rather than on the .container div, which has a fixed height. Without the inner, relatively positioned div, the .full-height div will always calculate its dimensions and position based on .container.

* {
  box-sizing: border-box;
}

.container {
  position: relative;
  border: solid 1px red;
  height: 256px;
  width: 256px;
  overflow: auto;
  float: left;
  margin-right: 16px;
}

.inner {
  position: relative;
  height: auto;
}

.full-height {
  position: absolute;
  top: 0;
  left: 0;
  right: 128px;
  bottom: 0;
  height: 100%;
  background: blue;
}

<div class="container">
  <div class="full-height">
  </div>
</div>

<div class="container">
  <div class="inner">
    <div class="full-height">
    </div>

    Lorem ipsum dolor sit amet, consectetur adipisicing elit. Aspernatur mollitia maxime facere quae cumque perferendis cum atque quia repellendus rerum eaque quod quibusdam incidunt blanditiis possimus temporibus reiciendis deserunt sequi eveniet necessitatibus
    maiores quas assumenda voluptate qui odio laboriosam totam repudiandae? Doloremque dignissimos voluptatibus eveniet rem quasi minus ex cumque esse culpa cupiditate cum architecto! Facilis deleniti unde suscipit minima obcaecati vero ea soluta odio
    cupiditate placeat vitae nesciunt quis alias dolorum nemo sint facere. Deleniti itaque incidunt eligendi qui nemo corporis ducimus beatae consequatur est iusto dolorum consequuntur vero debitis saepe voluptatem impedit sint ea numquam quia voluptate
    quidem.
  </div>
</div>

http://jsfiddle.net/M5cTN/