core-js is the more common of the two in our index: it runs on 16,794 websites against 9 for SpriteSpin, and 3 sites use both. Counts come from real scans, not vendor claims.
core-js is a modular standard library for JavaScript, with polyfills for cutting-edge ECMAScript features.
SpriteSpin is a JavaScript plugin that enables users to create 360-degree image spin animations on their websites.
3 sites run both core-js and SpriteSpin. That is 33% of the sites using SpriteSpin, the smaller of the two.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.