Firefox Tasks in One Popup: A Complete Guide to Fox Toolbox

Fox Toolbox is a Firefox extension that combines current-tab controls, media downloads, ad blocking, web-tab locking, and browsing-data deletion in one tool.

As of version 2.2.0, it supports Firefox 128 and later. Clicking its toolbar icon opens a 600×600 popup containing nine tools in a 3×3 grid. It is built as a Firefox Manifest V3 WebExtension, has no external runtime dependencies, and does not operate its own telemetry server.

It is disabled in private windows. Some tools also cannot work on protected Firefox pages, such as about: pages and the Add-ons Manager, where extensions are not allowed to inject code.

All features at a glance

• 01 Tab Volume: controls volume from 0% to 1000% and mute state independently for each tab.
• 02 Dark Mode: provides Off, Compatible, Balanced, and Strong levels.
• 03 User-Agent: changes the current tab's User-Agent using 69 presets.
• 04 Images: detects and downloads images from the current page and accessible iframes.
• 05 Video: detects directly accessible video and audio URLs and downloads them.
• 06 Save Site: packages the current HTML and linked CSS and JavaScript into a ZIP file.
• 07 Ad Blocking: provides Off, Standard, and Strict rules plus a site allowlist.
• 08 Tab Lock: places a password-protected lock screen over ordinary web tabs.
• 09 Kill Switch: deletes selected browsing data after an explicit confirmation step.

1. Tab Volume

Tab Volume adjusts the current tab independently of other tabs, from 0% through 1000%. It provides quick buttons for 100%, 250%, 500%, and 1000%, as well as a mute button. Unmuting restores the previous volume.

It does more than locate a single <video> element.

• Standard HTML <audio> and <video> elements
• Media inside accessible iframes
• Media elements added to the page later
• Media inside Shadow DOM
• Sound produced through the Web Audio API

The browser limits the volume property of ordinary HTML media to 1, or 100%. The original media element is therefore capped at 100%, while Web Audio output can pass through a separate Gain node and be amplified up to ten times. Results above 100% vary according to how a site implements audio.

At 0%, Fox Toolbox also uses Firefox's native tab mute. It remembers whether the extension itself owns that mute state, so it does not accidentally unmute a tab that the user had already muted.

Per-tab values are associated with the Firefox session. Restoring a tab also restores its volume, and the toolbar badge shows the active volume or lock state.

2. Dark Mode

Dark Mode offers four compatibility levels instead of applying one universal filter.

• Off: removes the added styles and uses the site's original design.
• Compatible: tells the browser to use a dark color scheme and darkens only the basic background. It suits sites that already provide partial dark-mode support.
• Balanced: inverts the page colors, then reverses the effect for images and video. It suits ordinary documents and bright pages.
• Strong: directly overrides backgrounds, text, borders, and form-control colors. Use it when the other levels do not make a site dark enough.

The selected mode can apply temporarily to the current tab or be remembered as the default for that site. Per-site settings are stored by hostname in Firefox's local extension storage.

Higher levels override more CSS, so images, SVG, code editors, maps, canvases, or complex layouts may look wrong. If that happens, lower the level or turn the feature off and reload the tab.

3. Changing the User-Agent

The User-Agent tool currently provides 69 presets.

• Chrome, Edge, Firefox, and Safari
• Windows, macOS, and Linux
• iPhone and iPad
• Several Android devices
• Search-engine bots

Selecting a preset changes the User-Agent header on requests from the current tab and adjusts the page-visible navigator.userAgent, appVersion, platform, and vendor values. The tab is then reloaded. The setting is implemented as a per-tab session rule, so other tabs are not changed at the same time.

This is a compatibility-testing aid, not complete device impersonation.

• User-Agent Client Hints
• TLS connection characteristics
• The real screen size and input devices
• Firefox's rendering engine
• Other browser fingerprinting data

Those values can remain unchanged. A site may compare inconsistent signals and detect the override, so the tool should not be treated as an authentication, tracking-protection, or security-bypass mechanism.

4. Image Downloader

The Image Downloader inspects the current document and accessible iframes and gathers images from several sources.

• src and the actually selected currentSrc of <img> elements
• Candidates from srcset and <picture>
• CSS background-image values
• Open Graph and Twitter preview images
• Image resources already loaded by the browser

Duplicate URLs are merged. Selected HTTP(S) or data: images are downloaded directly under Fox Toolbox/<site>/images/ in the default download directory. If a filename already exists, the extension generates a unique name instead of overwriting the file.

Lazy-loaded images that the page has not requested yet may be missing. Scrolling to the bottom of the page before scanning again can reveal more results.

One scan keeps at most 250 image and video entries combined in session storage. Up to 50 items can be downloaded in one batch, so larger result sets must be saved in multiple selections.

5. Video Downloader

Despite its name, the Video Downloader also finds directly accessible audio sources.

• Current sources of <video> and <audio> elements
• Nested <source> elements
• Links that directly target media files
• Video and audio resources already observed by the browser

Directly accessible files are saved under Fox Toolbox/<site>/videos/ in the default download directory. For cross-origin files, the extension supplies source-page information as the Referer where possible.

The following content cannot be turned into a finished video file by this tool.

• DRM-protected content
• blob: URLs and Media Source Extensions streams
• Segmented HLS .m3u8 streams
• DASH .mpd streams

Fox Toolbox does not merge streaming segments or decrypt DRM. Login sessions, expiring tokens, and anti-hotlinking policies can also make a detected item fail to download. Check the site's terms of service and copyright rules before saving media.

6. Site Download

Site Download clones the currently rendered HTML and gathers its linked CSS and JavaScript into a ZIP file.

Relative URLs in the document are converted to absolute URLs. URLs for CSS and JavaScript that were successfully fetched are rewritten to paths inside the ZIP. Accessible cross-origin resources are included as well.

The ZIP contains the following structure.

index.html
assets/
  styles/
  scripts/
fox-toolbox-report.json

fox-toolbox-report.json records the source URL, capture time, saved files, missing resources, and failure reasons.

This feature is not an unlimited whole-site copier.

• Current HTML: up to 12 MB
• Number of CSS and JavaScript resources: up to 160
• Size of one resource: up to 8 MB
• Total collected file size: up to 60 MB
• Resource request timeout: 12 seconds per file

If the HTML exceeds 12 MB, the operation stops rather than creating a damaged partial document. Dynamic API responses, Service Worker state, login sessions, databases, and DRM media are not fully reproduced.

Opening the downloaded index.html may execute the site's bundled JavaScript. Open it only when you trust the source, or inspect unknown pages in an isolated environment with JavaScript disabled.

7. Ad Blocking

Ad Blocking is a lightweight feature based on Firefox's declarative network-request rules.

• Off: disables the built-in blocking rules.
• Standard: enables the default rules and is the initial Fox Toolbox setting.
• Strict: enables both the standard and additional strict rules.

The current site can be added to an allowlist, which gives that hostname priority over the blocking rules. This lets you repair a frequently used site without disabling ad blocking everywhere.

Because the feature relies on its bundled rules, it cannot guarantee that every advertisement, tracking script, or newly created domain will be blocked. Strict mode can also block legitimate resources and break sign-in, payments, video playback, or page layout.

8. Web Tab Lock

Web Tab Lock uses a password from 6 to 128 characters to lock ordinary web tabs. It can lock them automatically when Firefox starts or immediately on manual request.

While locked, it displays a modal overlay above ordinary pages and blocks mouse, keyboard, touch, wheel, and context-menu input. For protected Firefox pages where code injection is prohibited, it opens a separate lock page.

The plaintext password is never stored.

1. A random 16-byte salt is generated.
2. PBKDF2-SHA-256 is applied for 240,000 iterations.
3. Only the derived hash and salt are stored in Firefox's local extension storage.

After five consecutive failures, another attempt is blocked for 30 seconds. Further failures increase the delay up to a maximum of 120 seconds.

This is an extension-level soft lock, not a security boundary for the browser or operating system. It cannot prevent the following actions.

• Using the address bar, Firefox menus, settings, or internal about: pages
• Disabling or removing Fox Toolbox from the Add-ons Manager
• Using another Firefox profile or another browser
• Using a private window or Troubleshoot Mode
• Bypassing the overlay with developer tools or Firefox-level privileges
• Accessing operating-system files or files that were already downloaded

It therefore does not replace the operating system's screen lock, public-PC access controls, parental controls, or enterprise security products.

9. Kill Switch

The Kill Switch deletes selected browsing data stored by Firefox.

• Cache
• Cookies and login sessions
• Download history
• Form autofill data
• Browsing history
• IndexedDB
• Site local storage
• Service Worker data
• Saved passwords

The time range can be All Time, Last Hour, Last 24 Hours, or Last 7 Days. Firefox's API does not support time-limited cache deletion, so cache can be selected only with All Time.

A two-step confirmation reduces accidental activation. After selecting the data types, the user must type 삭제 within 30 seconds before deletion begins. Saved passwords are excluded by default. If Tab Lock is configured, the web tabs can be locked when deletion finishes.

Fox Toolbox cannot restore deleted data. Removing cookies signs the user out of sites, and removing saved passwords deletes entries from Firefox's password manager.

Deleting download history removes only Firefox's record of the downloads. It does not delete files already stored on disk. Bookmarks and Fox Toolbox's own settings are also outside the Kill Switch scope.

Default shortcuts

• Increase current-tab volume by 10%: Alt + Shift + ↑
• Decrease current-tab volume by 10%: Alt + Shift + ↓
• Toggle current-tab mute: Alt + Shift + M
• Lock web tabs immediately: Alt + Shift + L

If a shortcut conflicts with the operating system or another extension, change it in Add-ons Manager → Manage Extension Shortcuts. The immediate-lock shortcut works only after a password has been configured.

What are the permissions used for?

Because several tools are combined in one extension, its permissions are divided by responsibility.

• browsingData: deletes the browsing-data types selected in the Kill Switch
• declarativeNetRequestWithHostAccess: blocks ads and changes per-tab User-Agent request headers
• downloads: saves images, video, and site ZIP files
• scripting: restores the lock connection to ordinary web tabs that were already open
• sessions: restores per-tab volume, User-Agent, and dark-mode state
• storage: stores ad-block, per-site dark-mode, and lock settings
• tabs: identifies the current tab, mutes and reloads tabs, and propagates lock state
• webNavigation: detects media in the current page and accessible iframes
• <all_urls>: applies features to ordinary web pages and accesses resources explicitly requested by the user

Persistent settings remain in Firefox's local extension storage. Temporary data, such as lock state, the 30-second deletion token, and detected-media lists, uses memory-backed session storage.

The source contains no code that sends telemetry or user information to a Fox Toolbox server, and the manifest declares that no data is collected. Downloading media or a site ZIP necessarily requests resources from the original site, but those resources are not sent to a separate Fox Toolbox server.

Internal structure

Fox Toolbox separates feature responsibilities as follows.

• popup: settings and execution screens for the nine tools
• background: privileged Firefox operations such as downloads, browsing-data deletion, tab state, and ad-block rules
• Main World page code: HTML media, Web Audio, and navigator values
• Isolated Content Script: dark mode, media detection, site capture, and the lock overlay
• Declarative network rules: ad blocking and per-tab User-Agent request-header changes

When the popup sends a command, the background code verifies the request source and tab ID, then sends state to page code only when required. Per-tab volume, User-Agent, and dark mode are tied to Firefox session values, while ad blocking, site-specific dark mode, and lock settings remain in local storage.

Installation

To load the current source folder temporarily in Firefox:

1. Open about:debugging#/runtime/this-firefox in the address bar.
2. Select Load Temporary Add-on.
3. Choose manifest.json from the Fox Toolbox folder.
4. Open the Fox Toolbox icon on the toolbar.

If a distribution ZIP is available, it may be selected on the same page. If that Firefox environment does not accept a ZIP directly, extract it and select the enclosed manifest.json.

A temporary add-on is removed when Firefox fully exits. Permanent installation in standard Firefox requires a Mozilla-reviewed and signed .xpi, not an ordinary ZIP.

Conclusion

Fox Toolbox's main advantage is that it places frequently used tab and privacy tools in one quickly accessible screen. Per-tab restoration, per-site dark mode, ad-block exceptions, and deletion confirmation also reduce mistakes during everyday use.

It is not an all-purpose solution. The media downloader does not handle DRM or segmented streams, Site Download captures a snapshot of the current document, and a User-Agent override does not replace the full browser fingerprint. Web Tab Lock cannot replace an operating-system lock either.

When its scope and limitations are understood, Fox Toolbox can be a practical way to organize several Firefox tasks that would otherwise be scattered across separate controls and extensions.