LayoutTests/editing/execCommand/format-block.html

<script>
if (window.layoutTestController)
     layoutTestController.dumpEditingCallbacks();
</script>
<div id="description">This test uses FormatBlock to modify three of the paragraphs below</div>
<br>
<div style="border:1px solid black" contenteditable="true">
<p id="item1">Make Pre</p>
<br>
<div>Foo<br><span id="item2">Make h1</span><br>baz</div>
<br>
<address id="item3">Attempt to apply the current formatting here</address>
</div>

<script>
var s = window.getSelection();
var r = document.createRange();
var p1 = document.getElementById("item1");
var p2 = document.getElementById("item2");
var p3 = document.getElementById("item3");
s.setPosition(p1, 0);
document.execCommand("FormatBlock", false, "pre");
s.setPosition(p2, 0);
document.execCommand("FormatBlock", false, "h1");
s.setPosition(p3, 0);
document.execCommand("FormatBlock", false, "address");
</script>