<!DOCTYPE html>
<html>
    <head>
        <title>Column-span:all and nothing else</title>
    </head>
    <body>
        <p>You should see the word 'PASS' on a green background below</p>
        <div style="width:5em; background:green;">
            <div style="-webkit-column-span:all; column-span:all;">PASS<br>&nbsp;</div>
        </div>
    </body>
</html>