execute script before OnDisconnected method

Question

I want to execute js script before a connection is closed, for example when I closed the web-page or refresh it. I have OnDisconnected method on the server-side, and it works well, but I can`t use local storage, so and need to execute a script on the client-side (In my case save the date when the user is disconnected, to local storage)

Something like this:

connection.disconnected(function () {
    var date = new Date();
    localStorage.setItem("disconnDate", date);
});

UPDATE. Solved this problem this way:

window.onbeforeunload = function (e) {
    var date = new Date();
    localStorage.setItem("disconnDate", date);
};

Answer 1

You can use onclose method of Client-Side connection:

connection.onclose(() => {
    var date = new Date();
    localStorage.setItem("disconnDate", date);
});

UPDATE

If you want to work this code on leaving page. You can add such event listener

window.addEventListener('beforeunload', (event) => {
   connection.stop();
});