A Firefox and Chrome extension that automatically loads Amazon Smile (using HTTPS) when you navigate to an Amazon page, in order to have Amazon donate a portion of your purchase to the charity of your choice.
In addition to the main 'amazon.com' site, the extension will work on the UK (amazon.co.uk) and German (amazon.de) Amazon sites as well. There aren't any other country-specific Amazon sites that support Smile as of late 2017.
The extension requires Firefox version 57 (released November 2017) or newer to run under Firefox, or any recent Chrome version to run under Chrome.
It can be installed for Firefox through the normal Firefox add-on mechanism:
https://addons.mozilla.org/en-US/firefox/addon/amazon-smiley/
For Chrome, you can download this repo, and in Chrome, on the chrome://extensions page, check the 'Developer mode' checkbox at the top and then choose 'Load unpacked extension...' and select the base directory of this repo to load the extension.
The extension asks for only the minimum privileges needed to redirect requests.
Feedback and suggestions for improvement are welcome. This is my first browser extension.