<style>
ruby {
    float:left;
    column-count: 2;
}
</style>		
<ruby id=ruby>content</ruby>
Pass if no crash.
<script>
if (window.testRunner)
    testRunner.dumpAsText();
document.body.offsetHeight;
ruby.innerHTML="<button>click me</button>";	
styleSheet = document.styleSheets[0];
styleSheet.addRule('#ruby::before','content: counter(coun2)');
</script>