pseudo-before-after-in-content.html

<!DOCTYPE html>
<style>
    #elm::before, #elm::after { display:block; -webkit-column-span:all; background:yellow; content:".........."; }
</style>
<p>There should be five rectangles with identical sizes below. The first, third and fifth
    one should be blue with nothing inside. The second and fourth one should be yellow with some
    dots inside.</p>
<div style="-webkit-columns:4; line-height:100px; background:blue;">
    &nbsp;
    <span id="elm">&nbsp;</span>
    &nbsp;
</div>

chromium/third_party/blink/web_tests/fast/multicol/span/pseudo-before-after-in-content.html