How to handle jQuery ajax post error when navigating away from a page

Question

Is there a way to handle the error from an ajax request within JQuery such that when the user navigates away from the page, the resulting error is ignored?

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Answer 1

It looks like the answer to this is to examine the jqXHR.status. The XMLHttpRequest spec outlines these steps to set the status:

The status attribute must return the result of running these steps:

1. If the state is UNSENT or OPENED, return 0 and terminate these steps.

2. If the error flag is set, return 0 and terminate these steps.

3. Return the HTTP status code.¹

NOTE also: The error flag indicates some type of network error or request abortion. It is initially unset and is used during the DONE state.

From what I understand therefore, this code check should fix the issue:

    if (xhr.status == 0)
        alert('error');

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¹_{https://web.archive.org/web/20120204040047/http://www.w3.org/TR/XMLHttpRequest/#the-status-attribute}

Answer 2

Checking the status didn't work for me, but

// Ignore incomplete requests, likely due to navigating away from the page
if (jqXHR.readyState < 4) {
    return true;
} 

in the error handler did (4 being DONE).

Answer 3

I've had to handle this issue too a couple of times.

I'd recommend binding to the $(window).unload event, setting some variable somewhere, such as in your namespace (App.unloading = true) and then testing it in ajax error callbacks.

See http://api.jquery.com/unload/