Simon Willison’s Weblog

What is a Polyfill? Useful new term: a Polyfill is “a shim that mimics a future API providing fallback functionality to older browsers”.

Posted 9th October 2010 at 11:48 am

Recent articles

Vibe engineering - 7th October 2025
OpenAI DevDay 2025 live blog - 6th October 2025
Embracing the parallel coding agent lifestyle - 5th October 2025

browsers 89 recovered 213 polyfill 2 remy-sharp 3

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