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Desktop

Chrome (Windows/Mac/Linux)

Menu > Settings > Privacy and security > Site settings
JavaScript > choose Sites can use JavaScript
(Optional) Add sites under Allowed/Blocked

Microsoft Edge (Chromium)

Menu > Settings > Cookies and site permissions > JavaScript
Turn Allowed (recommended) on

Firefox

There's no normal menu toggle.
In the address bar type about:config
Accept the warning
Search javascript.enabled > set it to true
If it's already true but scripts don't run, check extensions like NoScript/uBlock

Safari (macOS)

Safari > Settings/Preferences > Security
Check Enable JavaScript.

Opera / Brave / Vivaldi

Same as Chrome (Chromium-based):

Settings > Privacy & security > Site settings > JavaScript > Allow

Mobile

Chrome for Android

Menu > Settings > Site settings > JavaScript > Allowed

Samsung Internet (Android)

Menu > Settings > Sites and downloads (or Site permissions) > JavaScript > Allow

Safari on iPhone/iPad

JavaScript is on by default in current iOS.
Older iOS: Settings app > Safari > Advanced > JavaScript toggle
If you don't see a toggle, it's already enabled

Check Content Blockers instead: Settings > Safari > Content Blockers

If it still doesn't work

Per-site blocks: Click the lock icon in the address bar > Site settings/Permissions > Allow JavaScript
Extensions: Disable script-blocking add-ons (NoScript, uBlock "disable JavaScript" mode, privacy tools)
Enterprise devices: Group Policy/MDM can force - disable JS - ask your admin
Clear cache and reload the page (Ctrl/Cmd+Shift+R)

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