Converts a number to currency format. Based on Alex G's comment at http://www.selfcontained.us/2008/04/22/format-currency-in-javascript-simplified/

toCurrency.js

function toCurrency(num) {
  var sign;
  var cents;
  var i;

  num = num.toString().replace(/\$|\,/g, '');
  if (isNaN(num)) {
    num = "0";
  }
  sign = (num == (num = Math.abs(num)));
  num = Math.floor(num * 100 + 0.50000000001);
  cents = num % 100;
  num = Math.floor(num / 100).toString();
  if (cents < 10) {
    cents = '0' + cents;
  }

  for (i = 0; i < Math.floor((num.length - (1 + i)) / 3); i++) {
    num = num.substring(0, num.length - (4 * i + 3)) + ',' + num.substring(num.length - (4 * i + 3));
  }

  return (((sign) ? '' : '-') + '$' + num + '.' + cents);
}