function-prototype-bind.js

if (! Function.prototype.bind) {
  Function.prototype.bind = function bind(context) {

    if (typeof this !== "function") {
      throw new TypeError("Function.prototype.bind: the object on which you're trying to bind to is not callable.")
    }

    var
      bound_func,
      func,
      func_arguments,
      noop_func
    ;

    func = this;
    func_arguments = Array.prototype.slice.call(arguments, 1);
    noop_func = function () {};

    bound_func = function () {
      var
        new_arguments
      ;

      new_arguments = func_arguments.concat(Array.prototype.slice.call(arguments));

      if (this instanceof noop_func && context) {
        return func.apply(this, new_arguments);
      } else {
        return func.apply(context, new_arguments);
      }
    };

    noop_func.prototype = this.prototype;
    bound_func.prototype = new noop_func();

    return bound_func;
  };
}