core-js vs parallax.js

core-js is the more common of the two in our index: it runs on 16,939 websites against 382 for parallax.js, and 183 sites use both. Counts come from real scans, not vendor claims.

core-js: 16,939
parallax.js: 382

core-js

core-js is a modular standard library for JavaScript, with polyfills for cutting-edge ECMAScript features.

Indexed sites: 16,939
Share of JavaScript libraries: 45%

Well-known sites using it

microsoft.com3.6.4
mail.ru3.26.1
dzen.ru2.6.12
azure.com3.25.0
cloud.microsoft3.33.0
gandi.net3.45.1

All 16,939 sites

parallax.js

Simple parallax scrolling effect.

Indexed sites: 382
Share of JavaScript libraries: 1%

Well-known sites using it

All 382 sites

Used together

183 sites run both core-js and parallax.js. That is 48% of the sites using parallax.js, the smaller of the two.

More comparisons

core-js vs jQueryJavaScript libraries
jQuery vs SwiperJavaScript libraries
jQuery vs jQuery MigrateJavaScript libraries
core-js vs SwiperJavaScript libraries
core-js vs jQuery MigrateJavaScript libraries
jQuery Migrate vs SwiperJavaScript libraries

Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.