Polyfill.io "Holy grail" approach

Polyfills are loading…

See the JavaScript tab for details. This approach:

• Uses feature detection in the browser
• Does not make a request if no polyfills are required
• Loads all polyfills in one file
• is asynchronous

About feature detection in the browser

Many people think that assessing browser capabilities by inspecting the user-agent identifier of the browser is a really bad idea. In fact, it's really OK, and literally all major websites do it.

Polyfill.io recommends using server-side feature detection for better performance and accuracy (detection is not always as straightforward as a simple ('thing' in OtherThing)) but for people who still want to do feature detection client side, this demo proves that polyfill.io does support that.