Run Javascript function only if 'beforeunload' function returns false

Question

Is there a way to execute javascript function if user click "not leave" in beforeunload alert?

I use JQuery and the following code:

$(window).on('beforeunload', function (e) {
    if (formSubmitting || !isDirty()) {
        return undefined;
    }
    var confirmationMessage = 'You have unsaved work.';
    (e || window.event).returnValue = confirmationMessage; //Gecko + IE
    return confirmationMessage; //Gecko + Webkit, Safari, Chrome etc.
});

So how to check, if user stays on the page or leave it?

possible duplicate of http://stackoverflow.com/questions/23522652/capture-the-result-of-window-onbeforeunload — ADyson, Aug 15 '16 at 08:52
your function doesn't make sense, just returning any value (except `undefined`) results in the same outcome, i.e. a default alert dialog like "This page is asking you to confirm that you want to leave - data you have entered may not be saved." is shown. — Simon Hänisch, Aug 15 '16 at 08:58
Simon Hänisch I edited it. I wanted to simplify it and did not realize this outcome. — H.W., Aug 15 '16 at 09:03

score 0 · Accepted Answer · answered Aug 15 '16 at 09:32

When beforeunload confirmation dialog is shown to the user, there are two possibilities:

User leaves the page: in this case unload event is fired.
User stays on page: nothing will happen.

So, leaving can be detected by unload event, however staying cannot be detected by an event.

Run Javascript function only if 'beforeunload' function returns false

1 Answers1