<style>
:first-letter {
    float: right;
    content: url()
}

body {
    columns: 2;
}
</style>
<body>First letter -PASS if no crash.<span id=outer><span id=inner>
<script>
if (window.testRunner)
    testRunner.dumpAsText();
outer.addEventListener("DOMSubtreeModified", function() {
    document.execCommand(false);
    document.body.style.setProperty("-webkit-columns","initial");
    inner.setAttribute("foobar","");
    document.body.style.setProperty("-webkit-writing-mode","vertical-lr");
    
});
outer.setAttribute("foobar","");
</script>