[javascript] Resource blocked due to MIME type mismatch (X-Content-Type-Options: nosniff)

I am developing a web page using JavaScript and HTML, everything was working good when I have received this list of errors from my HTML page:

The resource from “https://raw.githubusercontent.com/dataarts/dat.gui/master/build/dat.gui.min.js”
  was blocked due to MIME type mismatch (X-Content-Type-Options: nosniff).
The resource from “https://raw.githubusercontent.com/mrdoob/three.js/dev/build/three.js” was
  blocked due to MIME type mismatch (X-Content-Type-Options: nosniff).
The resource from “https://raw.githubusercontent.com/mrdoob/three.js/master/examples/js/renderers/CanvasRenderer.js”
  was blocked due to MIME type mismatch (X-Content-Type-Options: nosniff).
The resource from “https://raw.githubusercontent.com/mrdoob/three.js/master/examples/js/renderers/Projector.js”
  was blocked due to MIME type mismatch (X-Content-Type-Options: nosniff).
The resource from “https://raw.githubusercontent.com/mrdoob/three.js/dev/build/three.js” was
  blocked due to MIME type mismatch (X-Content-Type-Options: nosniff).

These errors appeared after an automatic browser update (Mozilla Firefox), may be something has been changed in the set up. Do you know any way to solve this problem?

This question is related to javascript mime

The answer is

I've solved this problem by changing charset in js-files from UTF-8 without BOM to simple UTF-8 in Notepad++

We started facing this error in production after our devops team changed the webserver configuration by adding X-Content-Type-Options: nosniff. Now, due to this, browser was forced to interpret the resources as it was mentioned in content-type parameter of response headers.

Now, from the beginning, our application server was explicitly setting content-type of the js files as text/plain. Since, X-Content-Type-Options: nosniff was not set in webserver, browser was automatically interpreting the js files as JavaScript files although the content-type was mentioned as text/plain. This is called as MIME-sniffing. Now, after setting X-Content-Type-Options: nosniff, browser was forced to not do the MIME-sniffing and take the content-type as mentioned in response headers. Due to this, it did interpret js files as plain text files and denied to execute them or blocked them. The same is shown in your errors.

Solution: is to make your server set the content-type of JS files as


This way, it will load all JS files normally and issue will get resolved.

See for the protocols HTTPS and HTTP

Sometimes if you are using mixed protocols [this happens mostly with JSONP callbacks ] you can end up in this ERROR.

Make sure both the web-page and the resource page have the same HTTP protocols.

I had this error when i was using the azure storage as a static website, the js files that are copied had the content type as text/plain; charset=utf-8 and i changed the content type to application/javascript

It started working.

https://cdn.rawgit.com is shutting down. Thus, one of the alternate options can be used. JSDeliver is a free cdn that can be used.

// load any GitHub release, commit, or branch

// note: we recommend using npm for projects that support it


// load jQuery v3.2.1

https://cdn.jsdelivr.net/gh/jquery/[email protected]/dist/jquery.min.js

// use a version range instead of a specific version

https://cdn.jsdelivr.net/gh/jquery/[email protected]/dist/jquery.min.js


// omit the version completely to get the latest one

// you should NOT use this in production


// add ".min" to any JS/CSS file to get a minified version

// if one doesn't exist, we'll generate it for you

https://cdn.jsdelivr.net/gh/jquery/[email protected]/src/core.min.js

// add / at the end to get a directory listing


ref - https://www.jsdelivr.com/?docs=gh

check your path ,this error will come if file was not exist into given path.

For Wordpress

In my case i just missed the slash "/" after get_template_directory_uri() so resulted / generated path was wrong:

My Wrong code :

wp_enqueue_script( 'retina-js', get_template_directory_uri().'js/retina.min.js' ); 

My Corrected Code :

wp_enqueue_script( 'retina-js', get_template_directory_uri().'/js/retina.min.js' );

This might be because the browser cannot access a file. I stumbled with this type of error when creating application with node.js. You can try to directly request the script file (copying and pasting url) and see if you can retrieve it. You can see then what the real problem is. It can be because of permission of folder in which the file is located, or browser just cannot find it due to incorrect path to it. In node.js, after specifying route to file, all works.

It happened to me for wrong tag. By mistake I add the js file in link tag.

Example: (The Wrong One)

<link rel="stylesheet" href="plugins/timepicker/bootstrap-timepicker.min.js">

It solved by using the correct tag for javascript. Example:

<script src="plugins/timepicker/bootstrap-timepicker.min.js"></script>

This can be fixed by changing your URL, example bad:

Content-Type: text/plain; charset=utf-8

Example good:

content-type: application/javascript;charset=utf-8

rawgit.com is a caching proxy service for github. You can also go there and interactively derive a corresponding URL for your original raw.githubusercontent.com URL. See its FAQ

i also facing this same problem in django server.So i changed DEBUG = True in settings.py file its working

It might be a wrong path. Ensure in your main app file you have:


Example link to your css as:

<link href="/css/clean-blog.min.css" rel="stylesheet">

similar for link to js files:

<script src="/js/clean-blog.min.js"></script>

Are you using express?

Check your path(note the "/" after /public/):

app.use(express.static(__dirname + "/public/"));

//note: you do not need the "/" before "css" because its already included above:

rel="stylesheet" href="css/style.css

Hope this helps

Check if the file path is correct and the file exists - in my case that was the issue - as I fixed it, the error disappeared