Public domain cryptocurrency pay-what-you-want widget for digital downloads with custom number spinners, conversion rates pulled on load, and QR-code generation. It was built for Bitcoin, Litecoin, and Dogecoin with conversions retrieved from the block.io API.
Demo: http://alotdog.github.io/coinvert/ (non-php/block.io version for static gh-pages branch with hard coded values)
Looks good across browsers and allow you to type values, use the clicky buttons, and use the up/down keys to scroll quickly. Rel measurements and no images for scalability.
Screenshot:
This is a very old project that existed mainly to help me learn git/github and DOM/styling. Besides being a mess of javascript and jQuery, there is precision loss when getting the conversion rate and the inability to have more than one widget. I don't feel like revisiting this right now, but I might clean it up in the future.
License: Public Domain / Unlicense
Implements jquery.qrcode.js https://github.com/jeromeetienne/jquery-qrcode (MIT License)