Polyfill
A polyfill is a piece of code that provides modern functionality on older browsers that do not natively support it. Developers use polyfills to allow them to write modern JavaScript while still maintaining compatibility for a wider range of users. However, loading unnecessary polyfills for modern browsers can add significant performance overhead.
Related web performance terms
- Page Load
Page Load refers to the entire process of a webpage becoming visible and interactive for a user, from the initial navigation request to the final rendering of content.
- Page Views (PIs)
Page Views is a metric that counts the total number of times a page on a website has been loaded or viewed by users. It is a fundamental measure of traffic and engagement.
- PageSpeed Insights (PSI)
PageSpeed Insights is a free tool from Google that analyzes the performance of a single webpage and provides suggestions for improvement.
- Passthrough Mode
Passthrough Mode is a temporary, protective state that Speed Kit enters when its Deployment Detection mechanism identifies a major website update.