<!DOCTYPE html>
<html>
<style>
    body { margin: 0; }

    .overlay {
        position: absolute;
        top: 0;
        left: 0;
        z-index: 2;
        width: 200px;
        height: 100px;
        background-color: green;
        opacity: 0.2;
    }
    .fill {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background-color: blue;
        opacity: 0.2;

        cursor: pointer;
    }
</style>
<body>
<div class="overlay">
    <div class="fill"></div>
</div>
<div class="overlay">
    <div class="fill"></div>
    <div class="fill"></div>
</div>

<pre id="results"></pre>
<script>
document.body.addEventListener("click", function(e) {
    console.log(e, "event delegation");
});

if (window.testRunner)
    testRunner.dumpAsText();

window.onload = function () {
    if (window.internals)
       results.textContent = internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_EVENT_REGION | internals.LAYER_TREE_INCLUDES_ROOT_LAYER_PROPERTIES);
};
</script>
</body>
</html>
