Since Ecma’s release of ECMAScript2015 (ES6), software companies have slowly added support for ES6 features and syntax. While most new browser versions support the majority of the ES6 library, there are still a couple sources of compatibility issues:

  • Some users have not updated to the latest, ES6 supported web browser version.
  • A few ES6 features, like modules, are still not supported by most web browsers.

Because companies add support for ES6 features gradually, it’s important for you to know how to look up browser support on a feature-by-feature basis. The website caniuse.com is the best resource for finding browser compatibility information.

In caniuse, you can enter an ES6 feature, like let, and see the percentage of browsers that recognize it. You can also see when each major web browser (Chrome, Safari, Edge, etc.) added support for the keyword.

The video to the right shows you how to get started with caniuse.com.


In the video, we will use caniuse.com to find the percentage of browsers that support the entire ES5 library, then we will look at the percentage of browsers that support modules, a feature introduced in ES6.

Folder Icon

Take this course for free

By signing up for Codecademy, you agree to Codecademy's Terms of Service & Privacy Policy.

Already have an account?