<!DOCTYPE html>
<html><head>
<meta http-equiv="content-type" content="text/html; charset=windows-1252">
<script>

function boom()
{
    x.style.display = "contents";
}

</script>
</head>
<body onload="boom();">

    <div style="-moz-column-width: 1px;">
        <div style="display: grid;">
            <div style="height: 200px;">v</div>
            <div style="height: 200px;" id="x">x</div>
        </div>
    </div>

</body>
</html>