天猫双十一狂抢优惠券？机智的程序猿这么玩

(function(window, document, undefined) {
    var interval = 800;
    var closeDelay = 200;
    var index = 0;
    var couponLinks;
    var getCoupon = function() {
        if (index >= couponLinks.length) {
            console.log("领取完毕");
            return;
        }
        var copOnLink= couponLinks[index];
        coponLink.click(); index++;
        console.log("领取 第" + index + " 张");
        setTimeout(getCoupon, interval);
        setTimeout(function() {
            var close = document.querySelector('.mui-dialog-close');
            if (close != null) close.click();
        }, closeDelay);
    };
    var _scrollTop = 0;
    var _scrollStep = document.documentElement.clientHeight;
    var _maxScrollTop = document.body.clientHeight - document.documentElement.clientHeight;
    var autoScrollDown = setInterval(function() {
        _scrollTop += _scrollStep;
        if (_scrollTop > _maxScrollTop) {
            clearInterval(autoScrollDown);
            couponLinks = document.querySelectorAll('.mui-act-item-yhqbtn');
            console.log("总共：" + couponLinks.length + "条张优惠券待领取...");
            getCoupon();
        } else {
            document.body.scrollTop = _scrollTop;
        }
    }, 500);
}) (window, document);

        var autoScrollDown = setInterval(function () {
            _scrollTop += _scrollStep;
            if (_scrollTop > _maxScrollTop) { //到底了就找出全部领取按钮
                clearInterval(autoScrollDown);
                couponLinks = document.querySelectorAll('.mui-act-item-yhqbtn');
                console.log("总共：" + couponLinks.length + "条张优惠券待领取...");
                getCoupon();
            } else {
                document.body.scrollTop = _scrollTop; //还没到底就滚屏
            }
        }, 500);

    var getCoupon = function() {
        if (index >= couponLinks.length) {  //领完了就不再执行定时器了
            console.log("领取完毕");
            return;
        }
        var copOnLink= couponLinks[index];
        coponLink.click(); index++;   //遍历优惠券按钮并触发点击事件
        console.log("领取 第" + index + " 张");
        setTimeout(getCoupon, interval);
        setTimeout(function() {  //200毫秒后触发关闭按钮
            var close = document.querySelector('.mui-dialog-close');
            if (close != null) close.click();
        }, closeDelay);
    };