ladybird/Tests/LibWeb/Text/input/Editing/execCommand-insertHorizontalRule.html

<script src="../include.js"></script>
<div contenteditable="true">foobar</div>
<script>
    test(() => {
        var divElm = document.querySelector('div');

        // Put cursor between 'foo' and 'bar'
        var range = document.createRange();
        getSelection().addRange(range);
        range.setStart(divElm.childNodes[0], 3);
        range.setEnd(divElm.childNodes[0], 3);

        // Insert horizontal rule
        document.execCommand('insertHorizontalRule');

        println(divElm.innerHTML);
    });
</script>