<!DOCTYPE html>
<style>
#multicol {
-webkit-column-count: 2;
-webkit-column-gap: 0;
column-count: 2;
column-gap: 0;
width: 200px;
height: 100px;
transform: translateZ(0);
}
.filler {
width: 100px;
height: 100px;
}
</style>
<div id="multicol">
<div class="filler"></div>
<div class="filler"></div>
</div>
<div id="layers"></div>
<script>
if (window.testRunner)
testRunner.dumpAsText();
if (window.internals)
document.getElementById("layers").innerText = internals.layerTreeAsText(document);
</script>