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

V&A East Storehouse and Operation Mincemeat in London - 27th August 2025
The Summer of Johann: prompt injections as far as the eye can see - 15th August 2025
Open weight LLMs exhibit inconsistent performance across providers - 15th August 2025

browsers 88 recovered 213 polyfill 2 remy-sharp 3

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