javascript - 重新加载浏览器后浏览器关闭时不显示警报，stackoverflow 网站也存在同样的问题

Question

我必须在浏览器关闭和刷新特定页面时显示警报。下面的代码适用于所有场景，但在下面的场景中失败。1.首先，做刷新，然后警报会来要求重新加载，现在重新加载。2.现在点击浏览器关闭按钮问题:- 现在在 chrome 和 Mozilla 浏览器中不会发出警报，在 Edge 中刷新时，多次发出警报我的代码是:-

window.onbeforeunload = (ev) => {
    let msg;
    debugger;
    if (sessionStorage.getItem('previousPage') === 'employee') {
       return 'Are you sure you want to navigate away?If you navigate away, your information will not be saved.'
        ev.preventDefault();
    }
    return msg;
};

请帮助我如何处理这种情况？

Answer 1

试试这个，与此非常相似:Clear localStorage on tab/browser close but not on refresh :

window.onbeforeunload = function (ev) {
    window.onunload = function () {
        let msg;
        debugger;
        if (sessionStorage.getItem('previousPage') === 'employee') {
           return 'Are you sure you want to navigate away?If you navigate away, your information will not be saved.'
            ev.preventDefault();
        }
        return msg;
    }
};