formatdollars.js

// Format a number into a dollar string.
Card.prototype.formatDollars = function(num) {
  var chars = (Math.round(num) + '').split('').reverse();
  var result = [];
  while (chars.length > 3) {
    result = result.concat(chars.slice(0, 3));
    result.push(',');
    chars = chars.slice(3);
  }
  result = result.concat(chars);
  return '$' + result.reverse().join('');
};