window.addEventListener('beforeunload', (event) => {

    localStorage.setItem("new_qus_id", $('.responseId').attr('id'));

    var new_qus_no = localStorage.getItem('new_qus_id');
    console.log(new_qus_no);

});

if (localStorage.getItem('new_qus_id') != '') {
    var question_id = localStorage.getItem('new_qus_id');
} else {
    var question_id = "<?php echo $question_id ; ?>";
}

你可以在JavaScript中使用beforeunload事件。

使用JavaScript，你可以这样做:

window.onbeforeunload = function() {
  localStorage.removeItem(key);
  return '';
};

这将在浏览器窗口/选项卡关闭之前删除键，并提示您确认关闭窗口/选项卡操作。我希望这能解决你的问题。

注意:onbeforeunload方法应该返回一个字符串。

There is a very specific use case in which any suggestion to use sessionStorage instead of localStorage does not really help. The use-case would be something as simple as having something stored while you have at least one tab opened, but invalidate it if you close the last tab remaining. If you need your values to be saved cross-tab and window, sessionStorage does not help you unless you complicate your life with listeners, like I have tried. In the meantime localStorage would be perfect for this, but it does the job 'too well', since your data will be waiting there even after a restart of the browser. I ended up using a custom code and logic that takes advantage of both.

I'd rather explain then give code. First store what you need to in localStorage, then also in localStorage create a counter that will contain the number of tabs that you have opened. This will be increased every time the page loads and decreased every time the page unloads. You can have your pick here of the events to use, I'd suggest 'load' and 'unload'. At the time you unload, you need to do the cleanup tasks that you'd like to when the counter reaches 0, meaning you're closing the last tab. Here comes the tricky part: I haven't found a reliable and generic way to tell the difference between a page reload or navigation inside the page and the closing of the tab. So If the data you store is not something that you can rebuild on load after checking that this is your first tab, then you cannot remove it at every refresh. Instead you need to store a flag in sessionStorage at every load before increasing the tab counter. Before storing this value, you can make a check to see if it already has a value and if it doesn't, this means you're loading into this session for the first time, meaning that you can do the cleanup at load if this value is not set and the counter is 0.

在这个问题被提出6年后，我发现这个问题仍然没有足够的答案;这应该实现以下所有:

关闭浏览器(或域的所有选项卡)后清除本地存储 如果至少有一个选项卡保持活动状态，则跨选项卡保留本地存储 重新加载单个选项卡时保留本地存储

在每个页面加载开始时执行这段javascript代码，以实现上述目标:

((nm,tm) => {
    const
            l = localStorage,
            s = sessionStorage,
            tabid = s.getItem(tm) || (newid => s.setItem(tm, newid) || newid)((Math.random() * 1e8).toFixed()),
            update = set => {
                let cur = JSON.parse(l.getItem(nm) || '{}');
                if (set && typeof cur[tabid] == 'undefined' && !Object.values(cur).reduce((a, b) => a + b, 0)) {
                    l.clear();
                    cur = {};
                }
                cur[tabid] = set;
                l.setItem(nm, JSON.stringify(cur));
            };
    update(1);
    window.onbeforeunload = () => update(0);
})('tabs','tabid');

编辑:这里的基本思想如下:

When starting from scratch, the session storage is assigned a random id in a key called tabid The local storage is then set with a key called tabs containing a object those key tabid is set to 1. When the tab is unloaded, the local storage's tabs is updated to an object containing tabid set to 0. If the tab is reloaded, it's first unloaded, and resumed. Since the session storage's key tabid exists, and so does the local storage tabs key with a sub-key of tabid the local storage is not cleared. When the browser is unloaded, all session storage will be cleared. When resuming the session storage tabid won't exists anymore and a new tabid will be generated. Since the local storage does not have a sub-key for this tabid, nor any other tabid (all session were closed), it's cleared. Upon a new created tab, a new tabid is generated in session storage, but since at least one tabs[tabid] exists, the local storage is not cleared

应该这样做，而不是使用delete操作符:

localStorage.removeItem(key);

如果您希望在浏览器关闭时删除键，则应该使用sessionStorage。