Convert numbers to Roman Numerals using JavaScript

to_roman.js

var toRoman = function(num){
  var range, numerals, roman_numeral, i;

  range = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
  numerals = "M CM D CD C XC L XL X IX V IV I".split(" ");
  roman_numeral = "";
  
  for(i=0;i<range.length;i++){
    while(num >= range[i]){
      num -= range[i];
      roman_numeral += numerals[i];
    }
  }
  return roman_numeral;
};

return toRoman;