Chrome Extension "Refused to load the script because it violates the following Content Security Policy directive"

Question

I'm trying to create a Chrome extension, but none of my JS works. The console shows this error:

Refused to load the script 'https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js' because it violates the following Content Security Policy directive: "script-src 'self' blob: filesystem: chrome-extension-resource:".

Why is it blocking my jQuery from running?

Solution 1

As explained on the Chome website, there is a Content Security Policy preventing your script to load remote script:

A relaxed policy definition which allows script resources to be loaded from example.com over HTTPS might look like:

"content_security_policy": "script-src 'self' https://example.com; object-src 'self'"

So in your case, the manifest.json should contain:

 {
  "name": "My Extension",
  "manifest_version": 2,
  "background":{
     "scripts": [...]
  },
  "content_security_policy": "script-src 'self' https://example.com; object-src 'self'",
 }

Solution 2

Did you allow it in your manifest JSON file. Something like this:

manifest.json

 {
   "name": "My Extension",
   "content_scripts": [{
     "js": ["jquery.min.js", "YourJavaScriptFile.js"],
     "matches": ["http://*/*", "https://*/*"]
   }]
 }

There are required fields I left out, but just giving the basic idea.

Solution 3

I will tell you long story short. Google Chrome has CSP (Content Security Policy), which means chrome extensions don't allow the external script. If you are using the vue cdn then just perform following steps and your are good to go.

• Add following code in your manifest.json and change your filenames as per need. Here 'unsafe-eval' is the thing you are looking for, just add this.

{
    "manifest_version": 2,
    "name"            : "Hello Extension",
    "version"         : "1.0",
    "permissions": [
        "https://cdn.jsdelivr.net/npm/vue/dist/vue.js"
    ],
    "background": {
        "scripts": ["popup.js"],
        "persistent": false
      },
    "description"     : "Testing the hello world extension",
    "icons": {
        "16"    : "icons16.png",
        "48"    : "icons16.png",
        "128"   : "icons16.png"
    },
    "browser_action": {
        "default_icon"   : "icons16.png",
        "default_popup" : "popup.html"
    },
    "content_security_policy": "script-src 'self' 'unsafe-eval' https://cdn.jsdelivr.net; object-src 'self'"
}

• In your external js here popup.js add the Vue code and everything will work great.

var app = new Vue({
    el: "#app",
    data: {
        name: ""
    }
});

Solution 4

Content Security Policy is another layer of security for your application. It lets you define all the origins from which you are loading any styles, scripts or data. For each of the style, script, font or connect, you need to specify the domains which you are loading in your application. If you are using a CDN jQuery of another domain, you need to specify this domain in the Content Security Policy.

If you don't want this added layer of security and would like to load styles or scripts from any domain you wish, just add this following meta tag in your index.html and make sure this is located before any of your imports.

<meta http-equiv="Content-Security-Policy" content="default-src *;">

here * is the wildcard character which lets you access any domain. If you want this added layer of security I suggest you go to the documentation which is very clear about how to specify all the domains you want import in your application

Solution 5

I found this solution

manifest V3

"content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'; script-src-elem 'self' 'unsafe-inline' https://music.yandex.ru/;"
}

View more solutions

Comments

[epascarello]

Did you add it to your manifest?

[Mia]

@epascarello That's the problem then, because I don't know what else I could be missing. How can I add it to the manifest?

[rsanchez]

Possible duplicate of Extension refuses to load the script due to Content Security Policy directive

[Mia]

Got it all setup now. Thank you for your help, it's worth a lot!

[Mia]

Well, that didn't go as planned. I now get the following console error: Uncaught ReferenceError: $ is not defined

[Jun711]

@serv-inc do u know what the syntax is for more than one endpoint?

[serv-inc]

@Jun: as of w3c.github.io/webappsec-csp/#header-content-security-policy, w3c.github.io/webappsec-csp/#grammardef-serialized-policy, and w3c.github.io/webappsec-csp/#grammardef-serialized-directive‌​, you should be able to just add the value (if you mean just add an element to script-src, otherwise, just add another directive with a semicolon ;)

[Jun711]

@serv-inc right, "content_security_policy": "script-src 'self' example.com example2.com; object-src 'self'", ; to mark the last one

[gumuruh]

loading external script is not allowed? But how to change it become allowed?

[john ktejik]

so what goes in example.com? The domain name? The jquery file? Can you give a complete example based on the OP's post?

[john ktejik]

I get a 'failed to load extension' after using this syntax

[gumuruh]

how to update that content_security_policy into manifest v3... as many people said there would be different.