Simple userscript that can allow you to toggle any event on the window object on or off

toggle-window-events.user.js

// ==UserScript==
// @name        window event toggler
// @namespace   https://gist.github.com/Sv443/b2768fdebc8a037fbde4f4df9f7443a2
// @match       https://*
// @grant       none
// @version     1.0
// @author      Sv443
// @license     WTFPL
// @run-at      document-start
// @connect     self
// ==/UserScript==

// which events you want to be able to toggle
const eventWhitelist = ["beforeunload"];

const listeners = [];

let eventsEnabled = true;
function disableEvents() {
  console.log("--- DISABLED EVENTS");
  eventsEnabled = false;
}
function enableEvents() {
  console.log("--- ENABLED EVENTS");
  eventsEnabled = true;
}

// toggles every 10 seconds for testing
setTimeout(disableEvents, 10_000);
setTimeout(enableEvents, 20_000);
setTimeout(disableEvents, 30_000);
setTimeout(enableEvents, 40_000);

// based on https://gist.github.com/alessioalex/fc536ef87713d0a9ed89
(function() {
  Error.stackTraceLimit = Infinity;

  (function(original) {
    window.__proto__.addEventListener = function(type, listener, useCapture) {
      if(eventWhitelist.includes(type)){
        listeners.push(listener);
        console.log('------> addEventListener ' + type, listener, useCapture);

        return original.apply(this, [
          arguments[0],
          (...a) => { if(eventsEnabled) arguments[1](...a); },
          ...arguments.slice(2),
        ]);
      }

      return original.apply(this, arguments);
    }
  })(window.__proto__.addEventListener);

  // bonus interceptor for removeEventListener if you want to hook into that as well
  (function(original) {
    window.__proto__.removeEventListener = function(type, listener, useCapture) {
      if(eventWhitelist.includes(type)){
        console.log('------> removeEventListener ' + type, listener, useCapture);
      }

      return original.apply(this, arguments);
    }
  })(window.__proto__.removeEventListener);
})();