<script>

        //1.在我们之前的项目里向原型链中集成方法时大多代码分析不严密，有时间我在这里会做详细分析;

        Array.prototype.each = function(fn) {

            try {

                this.i || (this.i = 0);

                //在这里，fn.constructor === Function保证了输入的构造类型

                if (this.length > 0 && fn.constructor === Function) {

                    while (this.i < this.length) {

                        var tmpEach = this[this.i];

                        //tmpEach.constructor === Array 保证了递归时的构造类型

                        if (tmpEach && tmpEach.constructor === Array) {

                            tmpEach.each(fn);

                        } else {

                            fn(tmpEach);

                        }

                        this.i ++;

                    }

                }

            } catch (ex) {

            }

            return this;

        }

        var v=[1,2,3,[4,5,[6,7]]];

        v.each(function(item){

            alert(item);

        });

    </script>