我不认为这里提出的解决方案是100%正确的，因为窗口。onbeforeunload事件不仅在浏览器/选项卡关闭时被调用(这是必需的)，而且在所有其他几个事件上也被调用。(可能不需要)

有关可以触发window.onbeforeunload的事件列表的更多信息，请参阅此链接

http://msdn.microsoft.com/en-us/library/ms536907 (VS.85) . aspx

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 ; ?>";
}

您可以简单地使用sessionStorage。因为sessionStorage允许在浏览器窗口关闭时清除所有键值。

看这里:SessionStorage- MDN

我不认为这里提出的解决方案是100%正确的，因为窗口。onbeforeunload事件不仅在浏览器/选项卡关闭时被调用(这是必需的)，而且在所有其他几个事件上也被调用。(可能不需要)

有关可以触发window.onbeforeunload的事件列表的更多信息，请参阅此链接

http://msdn.microsoft.com/en-us/library/ms536907 (VS.85) . aspx

这是一个老问题，但上面的答案似乎都不完美。

如果您希望存储身份验证或任何敏感信息，这些信息仅在浏览器关闭时被销毁，那么您可以依赖sessionStorage和localStorage进行跨选项卡消息传递。

基本上，这个想法是:

You bootstrap from no previous tab opened, thus both your localStorage and sessionStorage are empty (if not, you can clear the localStorage). You'll have to register a message event listener on the localStorage. The user authenticate/create a sensitive info on this tab (or any other tab opened on your domain). You update the sessionStorage to store the sensitive information, and use the localStorage to store this information, then delete it (you don't care about timing here, since the event was queued when the data changed). Any other tab opened at that time will be called back on the message event, and will update their sessionStorage with the sensitive information. If the user open a new tab on your domain, its sessionStorage will be empty. The code will have to set a key in the localStorage (for exemple: req). Any(all) other tab will be called back in the message event, see that key, and can answer with the sensitive information from their sessionStorage (like in 3), if they have such.

请注意，此方案不依赖于窗口。Onbeforeunload事件是脆弱的(因为浏览器可以关闭/崩溃而不触发这些事件)。此外，敏感信息存储在localStorage上的时间非常短(因为您依赖于跨选项卡消息事件的transcients更改检测)，因此此类敏感信息不太可能泄漏到用户的硬盘驱动器上。

下面是这个概念的演示:http://jsfiddle.net/oypdwxz7/2/

有五种方法可供选择:

setItem():将键和值添加到localStorage getItem():通过键从localStorage检索值 removeItem():按键从localStorage中删除一个项 clear():清除所有localStorage key():传递一个数字来检索localStorage的第n个键

您可以使用clear()，该方法在调用时清除该域的所有记录的整个存储。它不接收任何参数。

window.localStorage.clear();