javascript - onbeforeunload 在卸载中不起作用

Question

我编写了以下代码来在卸载中运行 onbeforeunload。但是，这似乎不起作用。有谁知道我的代码有什么问题，无论如何要让它工作？

$(window).unload(function () {
    if ($('.submitAction').val() == "" && isChange) {
        window.onbeforeunload = confirmExit;
    }
});

function confirmExit() {
    return "If you have made any changes to the fields without clicking the Save button, your changes will be lost.  Are you sure you want to exit this page?";
}

Answer 1

该onunload事件是当用户离开页面或关闭浏览器时触发的绝对最后一个事件。

onbeforeunload在事件中绑定到事件onunload将毫无意义，因为该事件已经发生（因此名称为onbeforeunload）。解决方案是在事件实际发生之前绑定到onbeforeunload事件，例如在页面加载时。

像这样的东西（未经测试）：

$(window).bind('beforeunload', function () {
    if ($('.submitAction').val() == "" && isChange) {
       return "If you have made any changes to the fields without clicking the Save button, your changes will be lost.  Are you sure you want to exit this page?";
    }
});

Answer 2

此行返回一个字符串：

return "If you have made any changes to the fields without clicking the Save button, your changes will be lost.  Are you sure you want to exit this page?";

我想你的意思是：

return window.confirm("If you have made any changes to the fields without clicking the Save button, your changes will be lost.  Are you sure you want to exit this page?");