<!DOCTYPE html>
<html>
    <head>
        <title>Spanner as ::before and ::after pseudo elements</title>
        <style>
            #elm::before, #elm::after { display:block; -webkit-column-span:all; column-span:all; background:yellow; content:".........."; }
        </style>
    </head>
    <body>
        <p>There should be three rectangles with identical sizes below. The first and third one
        should be yellow with some dots inside. The second one should be blue with nothing
        inside.</p>
        <div style="-webkit-columns:4; columns:4; orphans:1; widows:1; line-height:100px; background:blue;">
            <span id="elm">&nbsp;</span>
        </div>
    </body>
</html>