LayoutTests/editing/execCommand/format-block-with-braces.html

<script>
if (window.layoutTestController)
     layoutTestController.dumpEditingCallbacks();
</script>
<div id="description">This test uses FormatBlock with html brackets in the tag string passed to execCommand.</div>
<br>
<div style="display:inline" contenteditable="true" id="item1">
Format Me
</div>

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