bind_js3.js

var first_object = {
    a: 2,
    b: 4
};

function adder(val1, val2) {
    return this.a + this.b + val1 + val2;
}

Function.prototype.bind = function (obj) {
    var method = this,
        temp = function () {
            return method.apply(obj, arguments);
        };

    return temp;
}

var first = adder.bind(first_object);

console.log(first(5, 6));