String.prototype.format like python

String.prototype.format.js

(function (String) {
  String.prototype.format = function (args) {
    var copy = this + '';
    var i, len;
    for (i = 0, len = arguments.length; i < len; i++) {
      copy = copy.replace(new RegExp("\\{" + i + "\\}", 'g'), String(arguments[i]));
    }
    return copy;
  };
})(String);