Number.prototype.format = function(d_len, d_pt, t_pt) {
  var d_len = d_len || 0;
  var d_pt = d_pt || ".";
  var t_pt = t_pt || ",";
  if ((typeof d_len != "number")
    || (typeof d_pt != "string")
    || (typeof t_pt != "string")) {
    throw new Error("wrong parameters for method 'String.pad()'.");
  }
  var integer = "", decimal = "";
  var n = new String(this).split(/\./), i_len = n[0].length, i = 0;
  if (d_len > 0) {
    n[1] = (typeof n[1] != "undefined") ? n[1].substr(0, d_len) : "";
    decimal = d_pt.concat(n[1].pad(d_len, "0", String.PAD_RIGHT));
  }
  while (i_len > 0) {
    if ((++i % 3 == 1) && (i_len != n[0].length)) {
      integer = t_pt.concat(integer);
    }
    integer = n[0].substr(--i_len, 1).concat(integer);
  }
  return (integer + decimal);
}