Javascript 谷歌灯塔的手风琴菜单问题；“注册卸载侦听器”；

我的网站上手风琴菜单的Javascript有问题。菜单工作正常，但最新版本的谷歌灯塔现在告诉我Javascript有缺陷。Lighthouse现在抱怨脚本“注册了一个卸载侦听器”。该报告接着说：“<代码>卸载\代码>事件不可靠地启动，监听它可以阻止浏览器优化，如前向高速缓存。请考虑使用<代码>页隐藏< /代码>或<代码> VistiBuryTechange 事件。 有人能提出解决这个问题的方法吗

页面如下：

Javascript在这里：

(function(){
    var accs = document.querySelectorAll('.accordion, .accordionSecond'),
    cookiename = 'accordionpersiting_73561',
    persisted = document.cookie.match('(^|;)\x20*' + cookiename + '=([^;]*)'),
    persisting = {}, i = accs.length, toggleClass = accs[0] && accs[0].classList? 
        function(el, name){el.classList.toggle(name);} : function(el, name){
            var classes = el.className.split(' '), i = classes.length, has = false;
            while(--i > -1){if(classes[i] === name){has = true; classes.splice(i, 1); break;}}
            !has && classes.push(name);
            el.className = classes.join(' ');   
        };
    if(persisted && (persisted = persisted[2])){
        var p = persisted.split('.'), l = p.length;
        while(--l > -1){persisting[p[l]] = true;}
    }
    function clickfunction(trans){
        var panel = this.nextElementSibling;
        toggleClass(this, 'active');
        if(trans === false){toggleClass(panel, 'notransition');}
        panel.style.maxHeight = panel.style.maxHeight? null : panel.scrollHeight + "px";
        if(trans === false){panel.offsetHeight; toggleClass(panel, 'notransition');}
        persisting[this.getAttribute('data-index')] = !!panel.style.maxHeight;
    }
    while(--i > -1){
        accs[i].setAttribute('data-index', i);
        accs[i].addEventListener('click', clickfunction, false);
        persisting[i] && clickfunction.apply(accs[i], [false]);
    }
    window.addEventListener('unload', function(){
        var pa = [], p;
        for(p in persisting){persisting.hasOwnProperty(p) && persisting[p] && pa.push(p);}
        document.cookie = cookiename + "=" + pa.join('.') + "; path=/";
    }, false);
})();