A small YUI3 module which modifies Node's focus() function to take position argument "end" or number of characters and places cursor there.
<script type="text/javascript" src="http://yui.yahooapis.com/3.5.1/build/yui/yui-min.js"></script>
<script type="text/javascript" src="focusPosition.js"></script>
<script type="text/javascript">
YUI ().use ("focusPosition", function (Y) {
Y.one("textarea").focus ("end");
});
</script>