Auto-Clear Site Data 作者: byuserforuser

Auto-Clear Site Data

Automatically clears cookies, localStorage, indexedDB, cache, and service workers when you leave a site — whether you close a tab, navigate away, or the browser discards it. Stay private and keep your storage clean without lifting a finger. 🧹



✨ What It Does

• Auto-clears on exit — Data is wiped after a configurable delay (0–3600s) when you leave a site
• Clear on Startup — Optionally clean up leftover data from your last session
• Total Cookie Protection Ready — Completely clears cross-site partitioned cookies introduced by Firefox's Strict Enhanced Tracking Protection, leaving zero traces behind (only cookie)
• Manual "Clear Now" — One-click clearing with full control over what gets removed

🎛️ Flexible Exemptions

Create independent exemption rules for any site or pattern:

• Whitelist mode — Clear everything except your exempted sites
• Blacklist mode — Only clear data from sites you specify
• Per-container rules — Different exemptions for each Firefox Container
• Granular control — Choose exactly which data types to keep or clear per rule

🔍 Advanced Options

• Deep Clear — Also clear parent domain data (e.g., accounts.google.com → google.com)
• Redirect catching — Catch and clear sites you quickly pass through
• Deferred clearing — 3rd-party resources shared across tabs are cleared only when all tabs using them are closed
• Smart dependency tracking — Automatically tracks iframes and scripts, never clears data still in use
• Container support — Full Firefox Multi-Account Containers integration with per-container settings

🚀 When Data Gets Cleared

• ❌ Tab closed — Last tab of a site is closed
• 💤 Tab discarded — Browser unloads inactive tabs
• 🔀 Navigation — You navigate to a different domain
• 🚀 Startup — Optional cleanup from previous session

⚡ Built for Performance

• Batched API calls reduce browser overhead
• Smart dependency tracking prevents clearing data still in use
• Race-condition-safe architecture

🔒 Privacy First

100% local. Your settings and browsing habits never leave your device.



🔐 Permissions Explained

• tabs — Check if a site is still open before clearing its data
• browsingData — Actually clear cookies, cache, localStorage, etc.
• storage — Save your settings and exemption rules
• contextualIdentities — Support Firefox Containers
• webNavigation — Detect when you navigate away from a site
• cookies — Find all cookie names for browser.cookies.remove() api to remove partition cookies
• webRequest — Track iframes and 3rd-party scripts loaded by pages
• alarms — Schedule delayed clearing

Works on Firefox Desktop and Firefox Android.



⚠️ Known Limitations & Firefox Behaviors

1. Total Cookie Protection (TCP) & Partitioned Data

If you use Firefox with Total Cookie Protection enabled (Strict Enhanced Tracking Protection, or network.cookie.cookieBehavior = 5), Firefox isolates site data into specific partitions to prevent cross-site tracking.

• Cookies (Fixed): Partitioned cross-site cookies are fully supported and will be safely extracted and eradicated by this extension.
• LocalStorage, IndexedDB and others: Currently, the Firefox WebExtensions API lacks full support for selectively clearing partitioned data (like LocalStorage and IndexedDB) by hostname. As a result, cross-site partitioned folders for these types might not be completely cleared.
• Workaround (Not recommended): If you rely heavily on this extension to clear all cross-site storage, you can adjust your Enhanced Tracking Protection settings to Custom and select Cross-site and social media trackers (network.cookie.cookieBehavior = 4).

2. Leftover .metadata-v2 Files

After the extension clears a site's data, you might notice that an empty directory containing a .metadata-v2 file remains (e.g., in /storage/default/).

• Privacy Safe: Please rest assured that the actual data payload is completely safely cleared. The .metadata-v2 file is strictly an internal bookkeeping file managed by Firefox's QuotaManager. Websites have zero access to this file, meaning it cannot be used for tracking or as a supercookie.
• Why it's not deleted: Due to security sandboxing, WebExtensions do not have the filesystem permissions required to delete Firefox's internal root folders or metadata files.