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Starred by 24 users

Issue metadata

Status: Fixed
Closed: Nov 2017
EstimatedDays: ----
NextAction: ----
OS: Linux , Windows , Chrome , Mac
Pri: 1
Type: Bug

Blocked on:
issue 797712

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Issue 769012: Modules don't work in extensions

Reported by, Sep 26 2017 Project Member

Issue description

What steps will reproduce the problem?
1. Load an extension with the content below.

What is the expected result?
The extension should load without error (and should have access to the module).

What happens instead of that?
The module fails to load and gives the error:
"Failed to load module script: The server responded with a non-JavaScript MIME type of "". Strict MIME type checking is enforced for module scripts per HTML spec."

---  Extension  ---
// manifest.json
  "name": "foo",
  "description": "bar",
  "version": "0.1",
  "background": {"page": "background.html"}
  "manifest_version": 2

// background.html
<!doctype html>
<script src="background.js" type="module"></script>

// background.js
import {log} from '/module.js'

// module.js
export function log(data) { console.log(data); }

Comment 1 by, Sep 28 2017

Project Member
The following revision refers to this bug:

commit 6449de840aec46116c234a5865c4ba120a0e38d9
Author: Devlin Cronin <>
Date: Thu Sep 28 03:28:51 2017

[Extensions] Include mime type in served extension files

Modules enforce strict mime type requirements, but files served through
extension protocols don't specify a mime type. Include it in the
response headers. This enables modules for chrome extensions.

Add a test to exercise basic module use.

Bug:  769012 
Change-Id: I1eba64e9194c00b9feb39f5fb0f5576a53d34930
Commit-Queue: Devlin <>
Reviewed-by: Istiaque Ahmed <>
Reviewed-by: Matt Menke <>
Cr-Commit-Position: refs/heads/master@{#504885}

Comment 2 by, Sep 28 2017

cc: hiroshige
I think we only need to special case file URLs then.

Comment 3 by, Nov 10 2017

Status: Fixed (was: Started)

Comment 4 by, Nov 15 2017

Test failed on 64.0.3268.0 (Official Build) canary (64-bit) (cohort: Clang-64)

Comment 5 by, Nov 22 2017

Can reproduce this issue on chrome 64.0.3275.0 (Official Build) canary (64-bit) (cohort: Clang-64).

Why this issue status is fixed?

Comment 6 by, Nov 23 2017

Firefox has the same (or a very similar) bug. If you want script modules to also work in Firefox extensions, you can vote here:

Comment 7 by, Dec 22 2017

Comment 8 by, Dec 22 2017

#c7 did you mean to link to a different issue?

Comment 9 by, Dec 22 2017

#c8 yes, thanks for pointing out! this is the issue I wanted to refer to:

Comment 10 by, Dec 22 2017

Re #5: The fix for this issue landed in 63.0.3227.0. If you can still reproduce this issue, please provide a test case.

Comment 11 by, Dec 22 2017

 Issue 763673  has been merged into this issue.

Comment 12 by, Dec 27 2017

Re #10: there is an old issue (#c18 find out the reason and give a way to resovle this problem, but this issue mark as won't fix. and now this issue has a wide impact on modules/local-files, consider to deal this suitable, not ignore)

Comment 13 by, Dec 27 2017

Recent discussions: ~ #c30 (there is no following)

Comment 14 by, Dec 27 2017

Blockedon: 797712

Comment 15 by, Dec 27 2017

Components: Blink>HTML>Script
Thanks for heads up. Filed a new  Issue 797712  for tracking the particular issue caused by the local registry key.

(Leaving this issue closed as fixed, because the basic module script+extention issue has been fixed.)

Comment 16 by, May 4 2018

Project Member
The following revision refers to this bug:

commit 17d521bb5afbcc8d6ee95b46a4565351aee6d4fd
Author: Istiaque Ahmed <>
Date: Fri May 04 19:44:07 2018

Extensions: Add a test for importing modules from web

Bug:  769012 
Change-Id: Iae7e7ff1b338c2302476002c28dcc58378292404
Commit-Queue: Istiaque Ahmed <>
Reviewed-by: Devlin <>
Cr-Commit-Position: refs/heads/master@{#556156}

Comment 17 by, Jun 27 2018

 Issue 728377  has been merged into this issue.

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