I\'m trying to use the tabindex text input attribute to allow users to tab between fields on this page: https://seatgeek.com/login/. This works perfectly in all browsers (e
Something similar here and I found this to solve it on Firefox/Mac
The solution lies not in Firefox, but in the Mac OS X preferences.
Apple Menu > System Preferences > Keyboard and Mouse > Keyboard Shortcuts
and under "Full Keyboard Access" choose "All controls".
For newer macOS versions:
Apple > System Preferences > Keyboard > Shortcuts > Accessibility > All Controls (at the bottom of the pane)