Executing AJAX Function on onbeforeunload

In developing a chat application, it is often necessary to perform clean-up actions when a user closes the browser window. However, the window.onbeforeunload event executes asynchronously, making it difficult to execute AJAX calls before the page is unloaded.

To resolve this issue, it is recommended to explicitly set async: false in the AJAX settings. This forces the browser to wait for the AJAX request to complete before unloading the page. However, it is important to note that this may not be supported in all browsers.

Here's an adjusted version of the provided code:

window.onbeforeunload = closeSession;
function closeSession(){
    $.ajax({
        url: "/chat/process/chat.php",
        type: "GET",
        async: false // Force synchronous execution
    });
    return "disconnected";
}

In the PHP code, the deletion query can be executed as usual:

$delete= "DELETE FROM queue WHERE id = " . $_SESSION['CHAT_QUEUE_ID'];
// query, etc

By setting async to false in the AJAX request, you ensure that the database row is deleted before the page is unloaded, providing the desired clean-up functionality.