Anti-Tab-Detect

Chrome extension that completely prevents websites from detecting tab switches, page leaves, or window focus changes.

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What is it?

Some websites use various JavaScript APIs to detect whether the user has switched tabs, left the page, or moved the browser window out of focus. Anti-Tab-Detect blocks all known detection methods and makes websites believe the user is always active on the page.

Blocked Detection Methods

#	Method	Description
1	Page Visibility API	document.visibilityState → "visible", document.hidden → false
2	Event Listeners	visibilitychange, blur, focus, focusin, focusout, pagehide, pageshow, mouseenter, mouseleave, mouseover, mouseout
3	Inline Handlers	window.onblur, window.onfocus, document.onvisibilitychange etc. setters are disabled
4	document.hasFocus()	Always returns true
5	rAF + Time Consistency	requestAnimationFrame, performance.now(), Date.now() — consistent fake timeline
6	IntersectionObserver	Always reports isIntersecting: true, intersectionRatio: 1
7	Web Audio API	AudioContext.state → "running", statechange event silenced
8	Idle Detection API	IdleDetector.userState → "active", screenState → "unlocked"

Installation

1. Clone or download this repository:

   git clone https://github.com/Adilnasceng/anti-tab-detect.git

2. Open chrome://extensions in Chrome
3. Enable Developer mode (top right)
4. Click "Load unpacked"
5. Select the anti-tab-detect folder

Usage

• The extension is enabled by default when installed
• Click the extension icon in the toolbar to open the popup
• Use the toggle button to enable/disable
• Icon turns green when active, red when disabled
• State changes apply to newly opened tabs

Active → Blocking all detection methods
Inactive → Websites can detect normally

Testing

You can verify the extension is working using this online test tool:

https://webbrowsertools.com/test-always-active/

This site tests multiple tab detection methods. With the extension enabled, all tests should report that the tab is always active.

You can also verify manually via DevTools Console (F12):

document.visibilityState   // → "visible"
document.hidden            // → false
document.hasFocus()        // → true

You should see a [Anti-Tab-Detect] Aktif log in the console.

File Structure

anti-tab-detect/
├── manifest.json       # Manifest V3 configuration
├── content.js          # Main override script (MAIN world)
├── background.js       # Service worker — dynamic script registration & icon management
├── popup.html          # Popup UI
├── popup.js            # Toggle control
├── icons/
│   ├── icon-on-16.png  # Active icon (green) — 16x16
│   ├── icon-on-48.png  # Active icon (green) — 48x48
│   ├── icon-on-128.png # Active icon (green) — 128x128
│   ├── icon-off-16.png # Inactive icon (red) — 16x16
│   ├── icon-off-48.png # Inactive icon (red) — 48x48
│   └── icon-off-128.png# Inactive icon (red) — 128x128
├── LICENSE
└── README.md

Technical Details

• Manifest V3 format, compliant with modern Chrome standards
• Dynamic content script registration via chrome.scripting.registerContentScripts — controllable with toggle
• Content script runs in "world": "MAIN" (page's JS context, not isolated)
• "run_at": "document_start" ensures it loads before the page's own JavaScript
• Overrides EventTarget.prototype.addEventListener to work across all elements
• performance.now(), Date.now(), and requestAnimationFrame timestamps are cross-consistent — defeats advanced timing analysis
• Active/inactive state persisted via chrome.storage.local

MIT License © 2026 Adil NAS