<!DOCTYPE html>
<p>Change a static positioned child of an otherwise empty multicol container to fixed positioned.</p>
<p>There should be a blue <em>square</em> below.</p>
<div style="-webkit-columns:2; width:100px; background:blue;">
    <div style="-webkit-column-span:all; margin-bottom:100px;"></div>
    <div id="elm">
         <br>
    </div>
    <div style="-webkit-column-span:all; margin-top:100px;"></div>
</div>
<script>
    document.body.offsetTop;
    document.getElementById("elm").style.position = "absolute";
</script>