<!DOCTYPE html>
<html>
    <head>
        <title>Insert content into collapsable whitespace between two spanners</title>
        <script>
            function test() {
                var elm = document.getElementById('elm');
                document.body.offsetTop; // trigger layout
                elm.style.display = 'block';
            }
        </script>
        <style>
            .spanner { -webkit-column-span:all; column-span:all; }
        </style>
    </head>
    <body onload="test()">
        <p>There should be three lines below with the word "PASS". Letter spacing is expected to vary</p>
        <div style="float:left; overflow:hidden;">
            <div style="-webkit-columns:4; columns:4; column-gap:0; -webkit-column-gap:0; orphans:1; widows:1;">
                <div class="spanner">PASS</div>
                <div id="elm" style="display:none;">P<br>A<br>S<br>S</div>
                <div class="spanner">PASS</div>
            </div>
        </div>
    </body>
</html>