Javascript Number formatMoney(groupsDelimeter, fractionLength, fractionDelimeter)

Number.prototype.formatMoney = function(groupsDelimeter, fractionLength, fractionDelimeter){
  var n = this,/*  www. j  a v a 2 s  .  co  m*/
    c = isNaN(fractionLength = Math.abs(fractionLength)) ? 2 : fractionLength,
    d = fractionDelimeter == undefined ? "." : fractionDelimeter,
    t = groupsDelimeter == undefined ? "," : groupsDelimeter,
    s = n < 0 ? "-" : "",
    i = parseInt(n = Math.abs(+n || 0).toFixed(c)) + "",
    j = (j = i.length) > 3 ? j % 3 : 0;
  return s + (j ? i.substr(0, j) + t : "") + i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + t) + (c ? d + Math.abs(n - i).toFixed(c).slice(2) : "");
};