code: function checkMax(value, max) {
    if (max) {
      if (max.charAt(0) === '-') {
        if (value.charAt(0) !== '-')
          return false;
        return checkMax(max.substr(1), value.substr(1));
      } else {
        if (value.charAt(0) === '-')
          return true;
      }
      var len = Math.max(value.length, max.length);
      max = left0pad(max, len);
      value = left0pad(value, len);
      return value <= max;
    }
    return true;
  }
docs: max must be a 0 or positive number string