Block visibility tracking on Class

Blocks page visibility / unload tracking on the target page only

K instalaci tototo skriptu si budete muset nainstalovat rozšíření jako Tampermonkey, Greasemonkey nebo Violentmonkey.

You will need to install an extension such as Tampermonkey to install this script.

K instalaci tohoto skriptu si budete muset nainstalovat rozšíření jako Tampermonkey nebo Violentmonkey.

K instalaci tohoto skriptu si budete muset nainstalovat rozšíření jako Tampermonkey nebo Userscripts.

You will need to install an extension such as Tampermonkey to install this script.

K instalaci tohoto skriptu si budete muset nainstalovat manažer uživatelských skriptů.

(Už mám manažer uživatelských skriptů, nechte mě ho nainstalovat!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(Už mám manažer uživatelských stylů, nechte mě ho nainstalovat!)

// ==UserScript==
// @name         Block visibility tracking on Class
// @namespace    https://upc.blackboard.com
// @author       enzocipher
// @license      MIT
// @version      1.2
// @description  Blocks page visibility / unload tracking on the target page only
// @match        *://*.upc.blackboard.com/*
// @match        *://*.upc.class.com/*
// @run-at       document-start
// @grant        none
// ==/UserScript==

(() => {
  'use strict';

  const targetHost = location.hostname.endsWith('class.com');

  if (!targetHost) return;

  const forceVisible = () => 'visible';
  const forceFalse = () => false;

  try {
    Object.defineProperty(Document.prototype, 'visibilityState', {
      get: forceVisible,
      configurable: true,
    });
  } catch {}

  try {
    Object.defineProperty(Document.prototype, 'hidden', {
      get: forceFalse,
      configurable: true,
    });
  } catch {}

  try {
    Object.defineProperty(document, 'visibilityState', {
      get: forceVisible,
      configurable: true,
    });
  } catch {}

  try {
    Object.defineProperty(document, 'hidden', {
      get: forceFalse,
      configurable: true,
    });
  } catch {}

  try {
    Object.defineProperty(window, 'visibilityState', {
      get: forceVisible,
      configurable: true,
    });
  } catch {}

  try {
    Object.defineProperty(window, 'hidden', {
      get: forceFalse,
      configurable: true,
    });
  } catch {}

  try {
    Object.defineProperty(Document.prototype, 'hasFocus', {
      value: () => true,
      configurable: true,
    });
  } catch {}

  const originalAddEventListener = EventTarget.prototype.addEventListener;
  const blockedEvents = new Set(['visibilitychange', 'pagehide', 'beforeunload', 'blur']);

  EventTarget.prototype.addEventListener = function (type, listener, options) {
    const isTargetDocument = this === document;
    const isTargetWindow = this === window;

    if ((isTargetDocument && blockedEvents.has(type)) || (isTargetWindow && blockedEvents.has(type))) {
      return;
    }

    return originalAddEventListener.call(this, type, listener, options);
  };
})();