# Modernizr/Modernizr

Modernizr is a JavaScript library that detects HTML5 and CSS3 features in the user’s browser.

Repository: https://github.com/Modernizr/Modernizr
Canonical: https://ross.abutalabs.com/products/modernizr
Homepage: https://www.npmjs.com/package/modernizr
Language: JavaScript
License: MIT
License Family: permissive
Topics: modernizr, javascript, css3-features, javascript-library, feature-detection, hacktoberfest
Last push: 2026-08-12T16:31:33+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 8, longevity 100
- inputs: {"age_days": 6186, "days_push": 21, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 25694, forks 2926 (observed 2026-08-28T04:11:38.413922+00:00)

## What it is
Modernizr is a JavaScript library that detects which HTML5 and CSS3 features are supported in the user's browser. It exposes results as properties on a global Modernizr object and as CSS classes on the html element, enabling progressive enhancement.

## Use cases
- detect html5 and css3 feature support in the browser
- apply css fallbacks for unsupported browser features
- progressively enhance pages based on browser capabilities
- check if webgl, canvas, or svg is available at runtime
- write conditional javascript for older browsers

## When to choose
- you need granular, per-feature browser capability detection
- you support legacy browsers and want progressive enhancement
- you want feature classes on the html element for css styling

## When to avoid
- you only target evergreen modern browsers and use native CSS feature queries
- you need a full polyfill library rather than detection
- you rely on the outdated modernizr.com website instead of npm builds

## Facets
- artifact type: library
- maturity: maintenance
- function: ui-components, developer-tools
- domain: frontend, web-development, browser-extensions
- platform: browser
- tags: feature-detection, html5, css3, progressive-enhancement, browser-compatibility, nodejs, javascript

## Member repositories
- Modernizr/Modernizr (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:11:38.413922+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T16:56:00.432211+00:00, confidence not recorded.
  - readme: https://github.com/Modernizr/Modernizr (fetched 2026-08-28T04:11:38.413922+00:00, sha 4f88f5237027)
  - registry_npm: https://registry.npmjs.org/modernizr (fetched 2026-08-29T07:52:59.380730+00:00, sha bbb31d7bfe70)
- Data as of 2026-08-30T08:39:29.467469+00:00.