在onbeforeunload（）事件中使用Confirm（）

Question

I want a confirm box to come up before unloading a page, and if the user clicks ok there a function needs to be called before leaving the page and if he clicks on cancel it should stay on the same page.

window.onbeforeunload = function() {
    if (!submitFormOkay) {
        if (confirm("Are you sure you want to leave?")) {
            leavepage();
        } else {
            submitfromokay = true;
            location.reload();
        }
    }
}

Is there anyway I can make this work using JS?

Answer 1

No, you can't. The only way to somehow accomplish that goal is by returning a String -value from your onbeforeunload handler. Some browsers ( Chrome for instance), will use that String and display it in their default warning message. But other browsers, won't use it and just display a standard message, that gives the user a chance to interrupt the page unload.

// Chrome will use the 'Y U LEAVING' string in its warning message now
window.onbeforeunload = function() {
    if(!submitFormOkay) {
        return 'Y U LEAVING ?';
    }
};