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

Video: Building a tool to copy-paste share terminal sessions using Claude Code for web - 23rd October 2025
Dane Stuckey (OpenAI CISO) on prompt injection risks for ChatGPT Atlas - 22nd October 2025
Living dangerously with Claude - 22nd October 2025

browsers 91 recovered 213 polyfill 2 remy-sharp 3

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