JavaScript is by default enabled on the Firefox web browser for mobile. Option to disable JavaScript is no longer available on Firefox for mobile devices.
Firefox for mobile is available for both Android and iOS devices.
Firefox for Android supports add-ons which allow users to make changes to their browsers. Firefox supports a limited number of add-ons right now, they have stated that they will add more in the future.
Add-ons like uBlock Origin and NoScript Suite allows users to disable JavaScript in Firefox.
If you have not installed any add-ons in your browser, JavaScript is enabled and it’s not possible to disable it.
Firefox for iOS does not support add-ons. Users can not disable JavaScript in their Apple iPhones. Only Safari browser has the option to disable JavaScript in iOS.