Convert numbers to roman numerals

roman.js

var MIN = 1;
var MAX = 3999;
var CHARS = 'IVXLCDM  ';

function toRomanNumeral (input) {
  if (input > MAX || input < MIN) {
    throw new Error('Cannot convert number');
  }

  var offset     = CHARS.length - 3;
  var digit      = 0;
  var multiplyer = 1000;
  var roman      = '';

  while (multiplyer >= 1) {
    digit = Math.floor(input / multiplyer);
    roman += itor(digit, CHARS[offset], CHARS[offset+1], CHARS[offset+2]);
    input -= (digit * multiplyer);
    multiplyer /= 10;
    offset -= 2;
  }

  return roman;
}

function itor (n, I, V, X) {
  if (n == 0)  return '';
  if (n == 1)  return I;
  if (n == 2)  return I+I;
  if (n == 3)  return I+I+I;
  if (n == 4)  return I+V;
  if (n == 5)  return V;
  if (n == 6)  return V+I;
  if (n == 7)  return V+I+I;
  if (n == 8)  return V+I+I+I;
  if (n == 9)  return I+X;
  if (n == 10) return X;
};