modal-dialog-generated-content.html

<!DOCTYPE html>
<link rel="match" href="modal-dialog-generated-content-ref.html">
<link rel="help" href="https://fullscreen.spec.whatwg.org/#new-stacking-layer">
<style>
dialog {
    padding: 0px;
    border: none;
    margin: 0px;
    top: 100px;
    left: 100px;
    height: 100px;
    width: 100px;
    background: green;
    outline: none;
}

dialog::before {
    content: '::before';
    position: absolute;
    top: 0px;
}

dialog::after {
    content: '::after';
    position: absolute;
    bottom: 0px;
}

dialog::backdrop {
    position: absolute;
    top: 100px;
    left: 300px;
    height: 100px;
    width: 100px;
    background: green;
    content: 'THIS TEXT SHOULD NOT BE SEEN';
}

dialog::backdrop::before {
    content: '::backdrop::before';
    position: absolute;
    top: 0px;
    background: red;
}
dialog::backdrop::after {
    content: '::backdrop::after';
    position: absolute;
    bottom: 0px;
    background: red;
}
</style>
<body>
Test for a modal dialog with ::before, ::after, and ::backdrop. The test passes
if there are two green boxes, one with the texts "::before" and "::after" in it.
<dialog></dialog>
<script>
document.querySelector('dialog').showModal();
</script>
</body>

chromium/third_party/blink/web_tests/external/wpt/html/semantics/interactive-elements/the-dialog-element/modal-dialog-generated-content.html