LayoutTests/editing/execCommand/format-block-from-range-selection.html

<script src="../../resources/dump-as-markup.js"></script>
<div id="description">This test uses FormatBlock to apply the dl tag to a range of paragraphs with different block tags.</div>
<br>
<div id="test" style="border:1px solid black" contenteditable="true">
<pre id="start">Foo</pre>
<div>bar<br><span>baz</span><br>raz</div>
dar
<br>
<address id="end">yar</address>
</div>

<script>
var s = window.getSelection();
var start = document.getElementById("start").firstChild;
var end = document.getElementById("end").firstChild;
s.setBaseAndExtent(start, 2, end, 2);

Markup.description('This test uses FormatBlock to apply the dl tag to a range of paragraphs with different block tags.');
Markup.dump('test', 'before FormatBlock');

document.execCommand("FormatBlock", false, "dl");

Markup.dump('test', 'after FormatBlock');
</script>