JavaScript is enabled by default in Firefox, so if a website complains that it isn't working then there is usually a content blocking extension that is blocking content. If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content. *make sure your extensions and filters are updated to the latest version *https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems See also: *https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop