Firefox Extension - onPopupClose event?

Question

I have popup in which I need to update the data inside it in reactively. What function or event is needed to track when a popup closes?

Currently my code structure is as follows:

 let BG = browser.extension.getBackgroundPage(); let timer = BG.timer; function updatePageTime(secondsElapsed) { const content = document.getElementById("content"); content.innerHTML = "Current Time Spent: " + timer.getTimeElapsed(); } document.addEventListener("DOMContentLoaded", function () { timer.subscribe(updatePageTime); }); document.addEventListener("unload", function () { timer.unsubscribe(updatePageTime); }); 

The problem is that unload and beforeunload do not trigger on popup closes, thus I am unable to stop updates to a non-existant DOM.

Answer 1

Unfortunately I did not see that unload is defined on window and not document. Simply changing the document.addEventListener("unload" to window.addEventListener("unload" fixes the problem.