3 category: JavaScript libraries
7 [Polyfill.io](https://polyfill.io) is a service that serves JavaScript polyfills.
15 <script src="https://cdn.polyfill.io/v2/polyfill.min.js"></script>
20 This is the default script for Polyfill.io.
24 * [API example](https://polyfill.io/v2/docs/api) _(polyfill.io)_
25 * [List of features](https://polyfill.io/v2/docs/features) _(polyfill.io)_
29 ### For modern browsers
32 <script>if(!(window.Promise&&[].includes&&Object.assign&&window.Map)){document.write('<script src="https://cdn.polyfill.io/v2/polyfill.min.js"></scr'+'ipt>')}</script>
35 This only includes polyfill.io when necessary, skipping it for modern browsers for faster load times.
40 <script>if(!(window.fetch&&window.Promise&&[].includes&&Object.assign&&window.Map)){document.write('<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=default,fetch"></scr'+'ipt>')}</script>
43 This is the same as the previous, but also adds a polyfill for `window.fetch()`. We add a `window.fetch` check and loads the additional `fetch` feature.