扩展js添加each 迭代方法

Array.prototype.each = function (fn) {

    try {
        this.i || (this.i = 0);
        if (this.length > 0 && fn.constructor === Function) {
            while (this.i < this.length) {
                var item = this[this.i];
                if (e && this.constructor === Array) {
                    e.each(fn);
                } else {
                    //fn(item);
                    fn.apply(item, [item]);
                }
                this.i++;
            }
            this.i = null;
        }
    } catch (e) {

    }
    return this;
};