<script type="text/javascript">
function blah(obj) {
obj.[!]setAttribute("value", "I've been clicked")[/!];
obj.[!]setAttribute("id", "thatWasntSoHard")[/!];
alert(obj.id);
}
</script>
<input type="button" value="click me" id="theHardestButtonToButton" onclick="blah(this)" />