WebSentinel

Webpage monitoring extension for Chrome and Firefox.
Heavily inspired by the legendary Update Scanner for Firefox.

WebSentinel monitors web pages for content changes. It runs in the background and notifies you when pages update, with configurable sensitivity to filter out minor edits.

Features

• Granular Sensitivity: Choose between "Every Change", "Default" (significant edits), or "Low" (major updates only).
• Diff Viewer: See exactly what changed with a built-in visual diff tool (highlighted and side-by-side views).
• Local Processing: All checks happen locally in your browser — no external servers involved.
• Cloud Sync: Page list syncs across devices via Chrome/Firefox sync.
• Backup & Restore: Export and import your monitored pages as JSON.

Installation

Chrome (Developer Mode)

1. Clone the repository:

   git clone https://github.com/Leonard013/WebSentinel

2. Open chrome://extensions/
3. Enable Developer mode (toggle in the top-right corner).
4. Click Load unpacked and select the project root folder (contains manifest.json).

Firefox (Temporary Add-on)

1. Clone the repository:

   git clone https://github.com/Leonard013/WebSentinel

2. Copy manifest.firefox.json over manifest.json:

   cp manifest.firefox.json manifest.json

   Or use the build script to generate a Firefox package (see Build below).
3. Open about:debugging#/runtime/this-firefox
4. Click Load Temporary Add-on and select any file inside the project folder (e.g. manifest.json).

Note: Temporary add-ons are removed when Firefox closes. For permanent installation, submit the built .zip to addons.mozilla.org.

Quick Start

1. Click the WebSentinel icon in your browser toolbar.
2. Navigate to a page you want to track and click Add Page.
3. Configure Sensitivity:
   • Every Change: Detects even a single character change.
   • Default: Ignores minor formatting; detects changes of ~100+ words.
   • Low: Only triggers on major structural updates.
4. Click Save.

Build

Requires Node.js. Produces a .zip ready for store submission.

# Build for Chrome (default)
node build.js

# Build for Firefox
node build.js --firefox

# Build for both
node build.js --all

Output files:

• WebSentinel-v{VERSION}.zip — Chrome Web Store package
• WebSentinel-firefox-v{VERSION}.zip — Firefox Add-ons package

Project Structure

WebSentinel/
├── manifest.json              # Chrome extension manifest (MV3)
├── manifest.firefox.json      # Firefox extension manifest (MV3)
├── build.js                   # Build script (supports --chrome, --firefox, --all)
├── icons/                     # Extension icons
├── src/
│   ├── background/            # Service worker (alarms, scanning, message hub)
│   ├── lib/                   # Core logic (diff engine, storage, scanner, backup)
│   ├── popup/                 # Main popup UI
│   └── viewer/                # Diff viewer (highlighted + side-by-side)
└── test/                      # Browser-based unit tests

Browser Compatibility

Running Tests

Tests run in the browser (no CLI test runner):

python3 -m http.server 8000
# Open http://localhost:8000/test/run-tests.html

Quick smoke tests: open test/simple-test.html in the browser.