Modernizr is an open-source JavaScript library that helps you build the next generation of HTML5 and CSS3-powered websites.

Why use Modernizr?

Taking advantage of the new capabilities of HTML5 and CSS3 can mean sacrificing control over the experience in older browsers. Modernizr 2 is your starting point for making the best websites and applications that work exactly right no matter what browser or device your visitors use.

Thanks to the new Media Query tests and built-in YepNope.js micro-library as Modernizr.load(), you can now combine feature detection with media queries and conditional resource loading. That gives you the power and flexibility to optimize for every circumstance.

Check out the full list of features that Modernizr detects, or learn more about conditional resource loading with Modernizr.

Download Modernizr 2.5.2

Use the commented, uncompressed Development version to develop with and learn from.

Then, dive into the Production build tool and pick just the tests you need!

View documentation Development Uncompressed, 42 Kb Production Configure your build

Get started with Modernizr

While Modernizr gives you finer control over the experience through JavaScript-driven feature detection, it is important to continue to use best practices throughout your development process. Use progressive enhancement wherever you can, and don’t sacrifice accessibility for convenience or performance.

Documentation: Getting started Taking Advantage of HTML5 and CSS3 with Modernizr, Faruk Ateş How to use Modernizr, Inayaili de León Modernizr: front-end development done right, Ryan Seddon [wiki] The Undetectables: features that cannot be detected [wiki] Cross-browser Polyfills

Also check out our Resources section.

Tip: check our Modernizr test suite to quickly test your current browser’s features.