w3c/IntersectionObserver resource

Health v2 · maintenance only

Flags: no_releases no_license

Adoption not part of the score

3613 stars · 509 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

The W3C specification repository for the Intersection Observer browser API, written in Bikeshed, which defines how web pages efficiently observe visibility of DOM elements relative to the viewport. The formerly included polyfill is archived and no longer maintained since all major browsers ship native implementations.

Use cases

• detect when an element scrolls into the viewport
• implement lazy loading of images
• track ad or content viewability
• trigger animations on scroll
• learn how the Intersection Observer API works
• implement infinite scroll

When to choose

• you need the authoritative spec text for IntersectionObserver behavior
• you are implementing the API in a browser engine
• you want to check browser support and status of the standard

When to avoid

• you need a polyfill for older browsers - it is archived and unsupported
• you want a runnable library rather than a specification document
• you need element visibility tracking outside the browser DOM

Facets

learning-resource · maturity active

browser-extension ui-components web-scraping web-development frontend browser-extensions documentation browser web-standard specification intersection-observer polyfill-archived w3c dom-api lazy-loading scroll-visibility web-server

Member repositories

For agents

markdown · JSON · MCP: product_card(name="w3c/IntersectionObserver")