A Firefox extension that automatically discards (unloads) tabs that haven't been used for a configurable amount of time. Activity is detected via mouse movement, keyboard typing, and scrolling.
- Auto-unload idle tabs — Discards tabs idle for 10 minutes (configurable 1–120 min)
- Activity detection — Tracks mouse movement, key presses, clicks, and scrolling
- Pinned tab exemption — Pinned tabs are skipped by default
- Audible tab exemption — Tabs playing audio are skipped by default
- Popup settings — Enable/disable, adjust timeout, toggle exemptions
- Open
about:debuggingin Firefox - Click This Firefox → Load Temporary Add-on
- Select
manifest.jsonfrom this project folder
Temporary add-ons are removed when Firefox closes. For persistent installation, the extension must be signed by Mozilla.
| Component | Role |
|---|---|
content.js |
Injected into every page. Listens for mousemove, keydown, mousedown, and scroll events. Sends an activity message to the background (throttled to once per 5 seconds). |
background.js |
Maintains a map of tabId → lastActivityTimestamp. Runs a 1-minute alarm that checks all tabs — if a non-active tab's last activity exceeds the idle threshold, it is discarded via browser.tabs.discard(). |
popup.html/js/css |
Settings UI to toggle the extension, change the idle timeout, and configure exemptions. |
Discarding a tab unloads it from memory while keeping it in the tab bar. The tab title and favicon remain visible, and clicking the tab reloads it. No data is lost.
Open the popup by clicking the extension icon:
| Setting | Default | Description |
|---|---|---|
| Enabled | On | Master toggle |
| Unload after (minutes) | 10 | Idle threshold (1–120) |
| Skip pinned tabs | On | Never discard pinned tabs |
| Skip audible tabs | On | Never discard tabs playing audio |
No build step required. Edit the source files and reload the extension from about:debugging.
Apache 2.0