Async CSS/JS Requests
Async (asynchronous) requests are requests for CSS or JavaScript files that are loaded in the background without blocking the browser from rendering the rest of the page. Using async loading is a key performance optimization technique because it allows the user to see and interact with the initial page content much faster.
Related web performance terms
- A/B Testing
A/B testing is a method of comparing two versions of a webpage to see which one performs better. For example, an e-commerce store might show 50% of its visitors a green "Buy Now" button (Version A)…
- AVIF
AVIF (AV1 Image File Format) is a modern, next-generation image format that provides significantly better compression than older formats like JPEG and WebP.
- Abandonment Rate
Abandonment Rate is a metric that measures the percentage of users who start a specific process (like a checkout funnel or a sign-up form) but leave before completing it.
- Above the Fold
This is a term originally from newspaper design that now refers to the portion of a webpage that is visible to a user without having to scroll down. Content "above the fold" is the very first thing a user sees.