HTML - Modernizer

Getting Started

To start using Modernizr in your project, you need to include the Modernizr library in your HTML file. There are two main ways to do this: downloading Modernizr and including it in your project or using a Content Delivery Network (CDN).

Downloading Modernizr is simple. Visit the official Modernizr website ( and click on the "Download" button. You can choose between the development version, which includes comments and is not minified, or the production version, which is minified for better performance. Once downloaded, place the Modernizr JavaScript file in your project's directory and include it in your HTML file using the <script> tag, preferably in the <head> section:

Example: Include Modernizr using downloaded file

  <script src="path/to/modernizr.js"></script>

Using a CDN is another way to include Modernizr in your project. You can use the cdnjs CDN by adding this <script> tag to your HTML file:

Example: Include Modernizr using CDN

  <script src=""></script>

Make sure to replace 2.8.3 with the version of Modernizr you want to use. Using a CDN has faster loading times since the user's browser may have cached it from other websites.

Once you have included Modernizr in your project, you can start using its feature detection capabilities to check for HTML5 and CSS3 features and load polyfills and fallbacks when necessary.

Feature Detection

Feature detection is a technique used to check if a browser supports a particular feature or functionality. It allows you to write conditional code that runs different paths based on the presence or absence of a feature. Modernizr is a library that simplifies feature detection for HTML5 and CSS3 features.

With Modernizr, you can detect support for various HTML5 and CSS3 features. It adds classes to the <html> element indicating which features are supported by the browser.

Example: Using Modernizr with HTML5 and CSS3

<p>If the browser supports the HTML5 <canvas> element, Modernizr will add the canvas class to the <html> element. If not, it adds the no-canvas class instead.</p>

You can use these classes to apply different styles or behaviors based on feature support in your CSS:

Example: Applying different styles based on feature support

.canvas {
  /* Styles for browsers that support canvas */

.no-canvas {
  /* Fallback styles for browsers that don't support canvas */

In your JavaScript code, you can use Modernizr to check for feature support programmatically:

Example: Checking feature support in JavaScript

if (Modernizr.canvas) {
  // Code for browsers that support canvas
} else {
  // Fallback code for browsers that don't support canvas

Modernizr also provides a method called Modernizr.testAllProps() which allows you to test multiple CSS properties at once. It takes a property name as the first argument and an optional value as the second argument. It returns true if the browser supports the property with the specified value:

Example: Using Modernizr.testAllProps method

if (Modernizr.testAllProps('background', 'linear-gradient(to bottom, #000, #fff)')) {
  // Code for browsers that support linear gradients
} else {
  // Fallback code for browsers that don't support linear gradients

By using Modernizr's feature detection capabilities, you can write smart and adaptive code that handles different levels of browser support gracefully. This allows you to use modern HTML5 and CSS3 features while providing fallbacks for older browsers.

Conditional Loading

Conditional loading is a technique used to load specific resources, such as polyfills or fallbacks, based on whether a browser supports a particular feature. With Modernizr, you can use conditional loading to load resources only when necessary, improving performance and reducing unnecessary downloads.

Polyfills are scripts that mimic the behavior of modern features in older browsers that don't support them natively. Fallbacks are alternative solutions or styles used when a browser doesn't support a particular feature. Modernizr allows you to load polyfills and fallbacks conditionally based on feature detection results.

To use conditional loading with Modernizr, you can use the Modernizr.load() method. This method takes an object or an array of objects as its argument. Each object represents a resource to be loaded and the conditions under which it should be loaded.

Example: Conditional loading using Modernizr.load()

  test: Modernizr.classlist,
  nope: 'classList.js', // Polyfill for classList

The test property specifies the feature to be tested, in this case, Modernizr.classlist. If the browser doesn't support the classList API, the polyfill file classList.js will be loaded using the nope property.

You can also use Modernizr.load() to load different resources based on multiple feature tests:

Example: Conditional loading based on multiple feature tests

    test: Modernizr.geolocation,
    yep: 'geolocation.js', // Script to use geolocation
    nope: 'geolocation-fallback.js' // Fallback script
    test: Modernizr.localstorage,
    yep: 'localstorage-feature.js', // Script to use local storage
    nope: 'localstorage-fallback.js' // Fallback script

Multiple feature tests are specified in an array. If the browser supports geolocation, the geolocation.js script will be loaded. If not, the geolocation-fallback.js script will be loaded instead. Similarly, if the browser supports local storage, the localstorage-feature.js script will be loaded; otherwise, the localstorage-fallback.js script will be loaded.

Conditional loading with Modernizr helps you load resources selectively based on your browser's capabilities. This allows you to provide a tailored experience while optimizing performance by loading only necessary resources.

Customizing Modernizr

Modernizr lets you create custom builds for your project's needs. By default, Modernizr includes many feature tests, but you may not need all of them. Creating a custom build allows you to select only the needed tests, reducing file size and improving performance.

To create a custom Modernizr build, visit the official Modernizr website ( and use the online builder. The builder provides an interface where you can select specific feature tests for your custom build.

In the online builder, you'll find a list of available feature tests grouped into categories like "HTML5," "CSS," and "JavaScript." You can browse these categories and select the relevant tests for your project. For example, if your project uses HTML5 video and audio, you can select those specific tests.

You can also combine multiple feature tests to create more complex conditions. Modernizr allows you to use logical operators like AND (&&) and OR (||) to combine tests. This is useful when checking for a combination of features before loading a resource or applying a style.

Example: Combining Feature Tests

if (Modernizr.touch && Modernizr.geolocation) {
  // Code for devices that support both touch and geolocation
} else {
  // Fallback code for devices that don't support either touch or geolocation

Once you've selected the desired feature tests and combined them as needed, generate your custom Modernizr build. The online builder will generate a JavaScript file that includes only the selected tests, resulting in a smaller file size compared to the full library.

After downloading your custom build, include it in your project just like with any other JavaScript file:

Example: Including a Custom Modernizr Build

  <script src="path/to/custom-modernizr.js"></script>

By creating a custom Modernizr build, you optimize performance by including only necessary feature tests. This results in faster loading times and reduces unnecessary code in your project.

Remember to keep your custom build up-to-date as your project evolves. If new features or dependencies require additional tests, update your custom build by revisiting the online builder.