Every other browser allows styling scrollbars using CSS. Firefox was the only one that didn't and there's a 15 year old open bug on bugzilla about it. The work

Every other browser allows styling scrollbars using CSS. Firefox was the only one that didn't and there's a 15 year old open bug on bugzilla about it. The work around was to use JavaScript, just to make it work on Firefox. It can now be implemented in CSS, which makes it really easy for you to disable or change your preference as well putting the responsibility of style on CSS and not some annoying JavaScript.