Amazon Japan USD Price Converter

A Firefox extension that automatically converts Japanese Yen prices to USD on Amazon Japan (amazon.co.jp).

This extension is now available on the FireFox Addon Store. https://addons.mozilla.org/en-US/firefox/addon/amazon-japan-usd-converter/#

Features

• Real-time currency conversion using current exchange rates
• Toggle between two display modes:
• Show both currencies (¥1000 ($6.37))
• Show USD only ($6.37)
• Automatically converts all prices on the page
• Updates dynamically when new content loads
• Simple toolbar popup for easy settings
• Caches exchange rates locally
• Updates exchange rates every 6 hours
• Fallback rate if API is unavailable

Installation

From Firefox Add-ons

1. Visit Amazon Japan USD Converter on Firefox Add-ons
2. Click "Add to Firefox"

Manual Installation (Development)

1. Clone this repository
2. Open Firefox and navigate to about:debugging
3. Click "This Firefox" on the left sidebar
4. Click "Load Temporary Add-on"
5. Select any file in the extension's directory

Usage

1. Visit Amazon Japan
2. Prices will automatically convert to USD
3. Click the extension icon in the toolbar to: - Switch between display modes - See current exchange rate - Manually refresh the exchange rate

Technical Details

• Uses exchangerate-api.com for live currency rates
• Default fallback rate: 157 JPY = 1 USD
• Caches exchange rates in browser storage
• Updates rates every 6 hours
• Uses MutationObserver for dynamic content

Development

Files

• manifest.json: Extension configuration
• converter.js: Main conversion logic
• popup.html: Settings UI
• popup.js: Settings functionality
• icon.svg: Vector icon source
• icon48.png, icon96.png: Extension icons

Building

To create the extension package: 1. Select all files 2. Create a ZIP archive 3. Ensure manifest.json is at the root level of the ZIP

License

MIT License - See LICENSE file for details

Contributing

1. Fork the repository
2. Create your feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

Support

If you encounter any issues or have suggestions, please open an issue on GitHub.