1704918 - Loading module from “https://myhost/es2015-myscript.js" was blocked because of a disallowed MIME type (“”).

Status: RESOLVED INVALID

(Core :: DOM: Security, defect)

Description

[mahesh.wattamwar]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4466.0 Safari/537.36 Edg/91.0.855.0

Steps to reproduce:

Access a site that hasloads JavaSript with type = module. ASP.Net Core server returns the JavaScript file with Content-Type="application/javascript".

HTML contains <src> tags as below:

<script src="/dashboard/product/staticres/runtime-es2015.fb4cf017484ef7075fcf.js" type="module"></script><script src="/dashboard/product/staticres/runtime-es5.fb4cf017484ef7075fcf.js" nomodule="" defer=""></script><script src="/dashboard/product/staticres/polyfills-es5.973a06b532b45497610a.js" nomodule="" defer=""></script><script src="/dashboard/product/staticres/polyfills-es2015.402f35cdff303433dc47.js" type="module"></script><script src="/dashboard/product/staticres/scripts.71b8fb2c2937463f1f3d.js" defer=""></script><script src="/dashboard/product/staticres/main-es2015.dbf7a8b46b0692fcded2.js" type="module"></script><script src="/dashboard/product/staticres/main-es5.dbf7a8b46b0692fcded2.js" nomodule="" defer=""></script>

Actual results:

Firefox failed to load the file with following error

Loading module from “https://partner.microsoft.com/dashboard/product/staticres/runtime-es2015.fb4cf017484ef7075fcf.js” was blocked because of a disallowed MIME type (“”).

Expected results:

Firefox should have loaded the file.

Comment 1

[Hani Yacoub, Desktop QA]

Could you please offer an example of a website so we could easily reproduce the issue?
Thanks.

Comment 2

[Tom S. (please needinfo tschuster)]

This is expected behavior. Your sever needs to use a correct Content-Type header like text/javascript for JS files.