Content_script doesn't load

Add-ons Development
#1

Hi all, I am new on Add-ons and have what it is probably a silly question, however, I haven’t been able to load any content_script. I have tried to include the script in two ways, via the “manifest.json” with the “content_scripts” properties and using the “browser.tabs.executeScript()” method from the script.js file under the browserAction folder.
the current structure, manifest and script from where is injected of my project are as follows:

browserAction
|__index.html
|__script.js
|__style.css
background.js
content_script.js
manifest.json

manifest.json

{
	"manifest_version": 2,
	"name": "Highlight",
	"description": "Highlight text",
	"version": "0.0.1",
	"icons": {
		"64": "icons/icon.png"
	},
	"permissions": [
		"activeTab",
		"contextMenus"
	],
	"content_scripts": [
		{
			"matches": ["*://*.mozilla.org/*"],
			"js": ["content_script.js,"],
			"all_frames": true
		}
	],
	"background": {
        "scripts": [
            "background.js"
        ]
    },
	"browser_action": {
		"default_icon": {
			"64": "icons/icon.png"
		},
		"default_popup": "browserAction/index.html",
		"default_title": "Highlight"
	},
	"page_action": {
		"default_icon": {
			"64": "icons/icon.png"
		},
		"default_popup": "pageAction/index.html",
		"default_title": "Highlight"
	},
	"options_ui": {
		"page": "options/index.html"
	}
}

script.js

    function start() {
    function selectText() {
    let selectedText = '';

    if (window.getSelection) {
        selectedText = window.getSelection();
    } else if (document.getSelection) {
        selectedText = document.getSelection();
    } else if (document.selection) {
        selectedText = document.selection.createRange().text
    }
    
    console.log(selectedText.toString());
};

function onError(error) {
    console.log(error);
}

browser.tabs.executeScript({file: "../content_script/index.js"})
.then(selectText)
.catch(onError);

};
start();
#2

I see you’re using *.mozilla.org content scripts. Where are you testing? On developer.mozilla.org? If so, also make sure you’re not testing in a private window (or have permanent private browsing enabled).

Lastly, how do you decide if your content script ran?

#3

To add on what freaktechnik said, if you are trying this on one of the following domain listed at


it will fail and the page will log a CSP error.

#4

Thanks guys for your quick answer. The way I manage to made it work was removing “content_scripts” property from the manifest and just inject the script from the browser action file. It works just fine for what I need. The documentation pointed was really useful.