Untitled

<html>
<head>
	<script src="jquery-1.4.3.min.js" type="text/javascript" charset="utf-8"></script>
	<script type="text/javascript" charset="utf-8">
	$(function(){
		$('a').click(function(){
		var os = $('p').css('font-size');
		var num = parseFloat(os, 10);
		var uom = os.slice(-2)

		$('p').css('font-size', num / 1.4 + uom);

		if(this.id == 'larger'){
		$('p').css('font-size', num * 1.4 + uom);
		}
	})
	});
	</script>
</head>
<body>
	<a href="#" id="larger">Larger</a> <br />
	<a href="#" id="smaller" />Smaller</a>
	<p>Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas.</p>
</body>
</html>