咨询Firefox何时默认启用ES6 module type功能

Great question—this is a super common point of confusion with ES6 module support across browsers, so let’s break this down clearly.

First, let’s resolve the discrepancy you noticed with CanIUse: Firefox did start enabling ES6 modules by default starting in version 60, but there are two critical caveats that often make it feel like the feature isn’t working:

• Mandatory type="module" attribute: Your script tag must explicitly include type="module" to trigger module parsing. For example:

  <script type="module" src="your-module-code.js"></script>
  

  Without this attribute, Firefox will treat the file as a regular script and completely ignore import/export syntax.

• File protocol restriction: If you’re loading files directly via file:// (opening local HTML files in the browser without a server), Firefox still requires manual enablement of dom.moduleScripts.enabled in about:config for security reasons. This restriction doesn’t apply when loading files over HTTP/HTTPS (like via a local development server at http://localhost).

As for the future of default enablement: All modern, up-to-date versions of Firefox (version 60 and later, especially recent releases like 100+) fully support ES6 modules by default for HTTP/HTTPS contexts. You won’t need to ask users to tweak about:config settings anymore if they’re running a current Firefox version.

If you’re still hitting issues even with the correct setup, here are a few quick troubleshooting steps:

• Verify your Firefox version (go to Help > About Firefox to check and update to the latest stable release)
• Double-check that your server is serving files with the correct MIME types (most modern servers handle this automatically for .js files)
• Ensure you’re not mixing legacy syntax (like require()) with ES6 module syntax, which can cause conflicts

内容的提问来源于stack exchange，提问作者adviner