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3.13.0 • Public • Published


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

Modernizr tests which native CSS3 and HTML5 features are available in the current UA and makes the results available to you in two ways: as properties on a global Modernizr object, and as classes on the <html> element. This information allows you to progressively enhance your pages with a granular level of control over the experience.

New Asynchronous Event Listeners

Often times people want to know when an asynchronous test is done so they can allow their application to react to it. In the past, you've had to rely on watching properties or <html> classes. Only events on asynchronous tests are supported. Synchronous tests should be handled synchronously to improve speed and to maintain consistency.

The new API looks like this:

// Listen to a test, give it a callback
Modernizr.on('testname', function( result ) {
  if (result) {
    console.log('The test passed!');
  else {
    console.log('The test failed!');

We guarantee that we'll only invoke your function once (per time that you call on). We are currently not exposing a method for exposing the trigger functionality. Instead, if you'd like to have control over async tests, use the src/addTest feature, and any test that you set will automatically expose and trigger the on functionality.

Getting Started

  • Clone or download the repository
  • Install project dependencies with npm install

Building Modernizr

From javascript

Modernizr can be used programmatically via npm:

var modernizr = require("modernizr");

A build method is exposed for generating custom Modernizr builds. Example:

var modernizr = require("modernizr");{}, function (result) {
  console.log(result); // the build

The first parameter takes a JSON object of options and feature-detects to include. See lib/config-all.json for all available options.

The second parameter is a function invoked on task completion.

From the command-line

We also provide a command line interface for building modernizr. To see all available options run:


Or to generate everything in 'config-all.json' run this with npm:

npm start
//outputs to ./dist/modernizr-build.js

Testing Modernizr

To execute the tests using mocha-headless-chrome on the console run:

npm test

You can also run tests in the browser of your choice with this command:

npm run serve-gh-pages

and navigating to these two URLs:



These tests are considered deprecated. They are not included anymore in the default build and will be removed in the next major version:

  • touchevents (in 4.0)
  • unicode (in 4.0)

Code of Conduct

This project adheres to the Open Code of Conduct. By participating, you are expected to honor this code.


MIT License

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