Thousands of websites told to ditch Polyfill service after Chinese hackers hijack it to serve malware

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Website administrators are being urged to remove the Polyfill.io service immediately after it was found to be serving malware to site visitors.

A polyfill is a piece of code (typically JavaScript) used to provide modern functionality on older browsers that do not natively support it. The term originates from the idea of "filling in" the gaps in a browser's feature set, allowing developers to use modern web standards and APIs without worrying about compatibility issues. Polyfills enable developers to write code using the latest standards while ensuring it still works in older environments.