honestly i tried and was going to suggest that, but it didn't work.
i tried something like this ( this doesn't work totally )
HTML Code:
<html>
<body>
<script language=javascript>
document.getElementById('test').style.font-size=20px;
</script>
<div id='test'>
testing 1 2 3
</div>
</body>
</html>
now if you try some other attributes besides font-size, it works, .. i.e. document.getElementById('test').style.visibility=' hidden';
go figure, .. i don't know. let us know if you figure it out.