<p>This tests for a bug where content pasted at the end of a paragraph would be inserted into the next paragraph.  You should see 'helloworld' below.</p>
<div id="div" contenteditable="true">hello</div>

<script>
var div = document.getElementById("div");
var sel = window.getSelection();
sel.setPosition(div, 0);
sel.modify("move", "forward", "word");
document.execCommand("InsertHTML", false, "<span><div>world</div></span>");
</script>