<!DOCTYPE html>
<html>
    <head>
        <title>Insert spanner in empty multicol container</title>
        <script>
            function test() {
                var elm = document.getElementById('elm');
                document.body.offsetTop; // trigger layout
                elm.style.display = 'block';
            }
        </script>
    </head>
    <body onload="test()">
        <p>You should see the word 'PASS' below.</p>
        <div style="float:left; overflow:hidden;">
            <div style="-webkit-columns:3; columns:3;"><div id="elm" style="display:none; -webkit-column-span:all; column-span:all;">PASS</div></div>
        </div>
    </body>
</html>