Function.prototype.before = function(beforefn) {

            var __self = this;

            return function() {

                beforefn.apply(this, arguments);

                return __self.apply(this, arguments);

            };

        };

        Function.prototype.after = function(afterfn) {

            var __self = this;

            return function() {

                var ret = __self.apply(this, arguments);

                afterfn.apply(this, arguments);

                return ret;

            };

        };

        var func = function() {

            console.log(2);

        };

        func.before(function() {

            console.log(1);

        }).after(function() {

            console.log(3);

        })();