ES5のbindメソッドと同等の機能を、Functionオブジェクトの拡張で実現する。

bind.js

// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function/bind

if (!Function.prototype.bind) {

  Function.prototype.bind = function (oThis) {

    if (typeof this !== "function") // closest thing possible to the ECMAScript 5 internal IsCallable function
      throw new TypeError("Function.prototype.bind - what is trying to be fBound is not callable");

    var aArgs = Array.prototype.slice.call(arguments, 1), 
        fToBind = this, 
        fNOP = function () {},
        fBound = function () {
          return fToBind.apply(this instanceof fNOP ? this : oThis || window, aArgs.concat(Array.prototype.slice.call(arguments)));    
        };

    fNOP.prototype = this.prototype;
    fBound.prototype = new fNOP();

    return fBound;

  };

}