Turn JavaScript on or off for a site
The JavaScript button in the address bar turns JavaScript on or off for the site you’re on. Settings › Sites turns it off for every site.
A recipe site fills the page with pop-ups while you read, and it works fine without JavaScript.
- In the address bar, select the JavaScript button.
The tab reloads with JavaScript turned the other way for that site. The button’s tooltip says whether JavaScript is on and whether your rule set it.
Turn it off for every site
Section titled “Turn it off for every site”- Open Settings › Sites.
- Under Defaults, turn off Run JavaScript on every site.
Sites you allowed with the JavaScript button still run JavaScript.
Details
Section titled “Details”- The JavaScript button shows in the address bar unless you unpin it. The site settings menu has the same switch, under JavaScript, with a pin to put the button back.
- Turned off, most sites lose menus, video players, and sign-in.
- Your choice syncs to your other devices.
- On an address like
nas.example.com, the button changes that address alone. To cover all ofexample.com, use the site settings menu and pick All of example.com in its title. - A private window can’t change a site’s JavaScript, because the choice is saved and synced.
- To put a site back on the default, open its page in Settings › Sites and choose Default under JavaScript.
Related pages
Section titled “Related pages”© 2026 Ellm Tree, Inc. Sval is not officially associated with Mozilla or its products. Firefox is a trademark of the Mozilla Foundation in the US and other countries.