AI & the web
Polyfill
Code providing a feature where the environment lacks native support.
In everyday use
A site supplies a fallback implementation for an older browser.
What to keep in mind
A polyfill may have limitations or extra performance costs.
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Further reading
Original explanation and example by Perspectism. Further reading may cover the wider subject, rather than this exact wording. Edition updated 7 October 2026.
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