Duplicate Tab Closer

WHAT IT DOES

Duplicate Tab Closer automatically detects and closes duplicate tabs of the same URL within your browser session, helping you keep your tab bar clean and organized. When you open a tab with a URL that is already open in another tab, the extension immediately identifies it as a duplicate, shows a notification, and closes the new tab, keeping only the original. A badge in the corner of the page shows the total number of open tabs, giving you visibility into your tab usage. You can whitelist specific domains or URLs to allow duplicates on certain sites, and manual override options let you keep a duplicate tab if needed. The extension uses localStorage to track open tabs and heartbeat signals to keep the tab registry clean, ensuring accurate duplicate detection even across multiple windows.

WHERE IT RUNS

The extension works on every website with unique URLs, including complex single-page applications, traditional websites, and any page that can be opened in multiple tabs. It runs locally in your browser, using localStorage and window.name to track tabs without sending any data to external servers. The extension supports all major browsers and adapts to both desktop and mobile viewports seamlessly.

HOW TO USE

After installation, the extension automatically starts tracking open tabs. When you open a duplicate tab, a notification appears at the top of the page. The duplicate tab is automatically closed after a short delay. To keep a duplicate tab, click the "Keep this tab" button in the notification. To customize the experience, open the extension panel and toggle "Auto-close duplicates" to enable or disable automatic closing. Toggle "Show notification on duplicate" to show or hide the notification. Choose a duplicate detection strategy: Exact URL match, Domain match, or Domain + path match. To whitelist specific domains or URLs, enter them in the whitelist input and click "Add to Whitelist." Use the "Register This Tab" button to manually register the current tab. For per-site customization, enable or disable the extension on specific websites using the per-site controls.

THE ACTUAL MECHANISM — LOCALSTORAGE-BASED TAB TRACKING WITH HEARTBEAT CLEANUP

The extension uses a two-part tracking system. Each tab is assigned a unique ID using the window.name property, which persists across page reloads. When a tab is opened, the extension registers the tab's URL and ID in localStorage under the key 'bg_tabs', along with a timestamp. A heartbeat interval (every 10 seconds) updates the timestamp for the current tab, keeping it alive in the registry. A cleanup interval (every 30 seconds) removes entries with timestamps older than 60 seconds, preventing stale data from accumulating. When a new tab is opened, the extension checks the registry for any existing tab with the same URL (or normalized URL based on the selected strategy: exact, domain, or path). If a match is found, the extension marks the current tab as a duplicate, shows a notification (if enabled), and either auto-closes it or waits for user interaction. The duplicate tab is closed by calling window.close() and navigating to about:blank as a fallback. Whitelisted URLs are skipped entirely, allowing duplicates on specified sites. The extension handles page visibility changes and unload events to keep the registry accurate across tab switches and browser closures.

THE PANEL

The settings panel is a lightweight, draggable overlay that appears in the center of your screen. You can reposition it by clicking and dragging the title bar; release it near the screen edge and it will snap into place automatically. To collapse the panel into a compact title bar, click the minimize button, expanding it again with the same control. The panel is fully responsive, adapting to different screen resolutions with a minimum width of 300px and a maximum of 480px. Press the Escape key at any time to dismiss the panel without applying changes. All controls—the enable/disable toggle, register tab button, auto-close toggle, notification toggle, strategy selector, whitelist input and add button, clear whitelist button, and per-site controls—are accessible within a clean, high-contrast interface that respects your system's color scheme.

PLEASE NOTE

This extension requires the free BotGentz companion extension to be installed and active, which provides the underlying DOM access and storage engine. The extension uses localStorage to track tabs, which is limited to the same browser session and may not work across different browsers or devices. Tabs that are closed without unloading (e.g., browser crashes) may leave stale entries in the registry, which are cleaned up within 60 seconds. The window.close() method may not work on tabs that were not opened by JavaScript; in such cases, the extension navigates to about:blank as a fallback. No personal data, browsing history, or tab data is ever collected, stored, or transmitted. All settings are saved using the browser's storage API and remain solely on your device. The extension does not inject ads, trackers, or analytics of any kind.