Function.prototype.bind

gistfile1.js

Function.prototype.bind = function (thisVal) {
    var target = this,
        args = [].slice.call(arguments, 1);
    function f () {
        return target.apply(
                this instanceof f ? this : thisVal, 
                args.concat([].slice.call(arguments))
        );
    };
    f.prototype = this.prototype;
    return f;
};