content-scripts-register-polyfill

Chrome/Safari extension polyfill for Firefox's browser.contentScripts.register()

Usage no npm install needed!

<script type="module">
  import contentScriptsRegisterPolyfill from 'https://cdn.skypack.dev/content-scripts-register-polyfill';
</script>

README

content-scripts-register-polyfill

WebExtensions: Polyfill for browser.contentScripts.register() for Chrome and Safari.

Install

You can download the standalone bundle and include it in your manifest.json.

npm install content-scripts-register-polyfill
import 'content-scripts-register-polyfill';

Usage

Include the script via manifest.json, then refer to the original contentScripts.register() documentation.

const registeredScript = await chrome.contentScripts.register({
    js: [{
        file: 'myfile.js'
    }],
    matches: [
        'https://google.com/*'
    ]
});

Additionally, if you're using webextension-polyfill, you can also use it with the original browser.* name: browser.contentsScripts.register()

const registeredScript = await browser.contentScripts.register({
    js: [{
        file: 'myfile.js'
    }],
    matches: [
        'https://google.com/*'
    ]
});

Usage as ponyfill

This package also exports a ponyfill, meaning you can also use it as a normal API isntead of treating it as a polyfill. This way it will always use the current code and never rely on Firefox’ native implementation.

import registerContentScript from 'content-scripts-register-polyfill/ponyfill.js';

const registeredScript = await registerContentScript({
    js: [{
        file: 'myfile.js'
    }],
    matches: [
        'https://google.com/*'
    ],
    excludeMatches: [ // Also supported
        'https://google.com/search*'
    ]
});

TypeScript

Starting in v3, the types are no longer included. You have a few options:

  • if you're using webextension-polyfill-ts it will automatically work
  • if you're using webextension-polyfill and the browser.* API, install its types
    npm install -D @types/firefox-webext-browser
    
  • if you want to use it as chrome.contentScripts.register() or as a ponyfill, you might need to install two type packages:
    npm install -D @types/firefox-webext-browser @types/chrome
    

Permission

Generally you don't need any permissions other than the host permission you want to register a script on.

However, in order to use allFrames: true you should the add webNavigation permission. Without it, allFrames: true won’t work:

  • when the iframe is not on the same domain as the top frame
  • when the iframe reloads or navigates to another page
  • when the iframe is not ready when runAt is configured to run (runAt: 'start' is unlikely to work)

If available, the webNavigation API will be automatically used in every situation for better performance.

Related

License

MIT © Federico Brigante