Live Example: (Read the CSS Newbie article)

Source Code: (Save the Source)

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>CSS Newbie Example: Currency Conversion</title>
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<script type="text/javascript">
function toUSD(number) {
    var number = number.toString(), 
    dollars = number.split('.')[0], 
    cents = (number.split('.')[1] || '') +'00';
    dollars = dollars.split('').reverse().join('')
        .replace(/(\d{3}(?!$))/g, '$1,')
        .split('').reverse().join('');
    return '$' + dollars + '.' + cents.slice(0, 2);
}

$(function() {
   $('#convert').click(function() { alert('Converted to: '+toUSD($('#number').val())); return false; });
});
</script>
<style>
#wrap {
   width: 75%;
   margin: 20px auto;
   font: 1em/1.5 Arial, Helvetica, sans-serif;
}
</style>
</head>
<body>
<div id="wrap">
  <h1>Currency Conversion Script</h1>
  <p>Enter a number in the box below and click Convert to see it rendered in US dollars.</p>
  <p><input type="text" id="number" /> <a href="#" id="convert">Convert!</a>
  <p><a href="http://www.cssnewbie.com/javascript-currency-conversion-script/">Return to the original article.</a></p>
</div>
</body>
</html>