JavaScript Switcher is a free Firefox extension designed for web developers who need granular control over JavaScript execution on specific domains. This tool introduces a convenient switch button in the URL bar, allowing users to easily enable or disable JavaScript on a per-domain basis. The extension remembers these settings for future visits, streamlining the development process by eliminating the need to repeatedly adjust JavaScript settings for individual sites.

Originally known as Quick JS Switcher, this extension is based on the JavaScript Control code, modified to enable JavaScript by default, responding to widespread user demand. However, it is important to note that due to current limitations on Firefox for Android, the URL bar icon does not dynamically change as expected, although it still functions correctly to block JavaScript by default and enable it with a click.