An "is not a function" error could indicate either that the site is not compatible with your older version of Firefox or that one of the site's script files did not load.

While viewing the page, try using Command+Shift+R (or Shift+click the Reload button on the toolbar) to flush old files and retrieve everything fresh, in case Firefox is mismatching files.

Sometimes anti-tracking features or ad-blocking add-ons can be responsible for blocked scripts. To temporarily disable tracking protection on Bluesky, click the "shield" icon at the left end of the address bar next to the lock. On the panel that drops down, click the blue slider switch to disable protection.

Any difference?

Thank you jshcher2000, I have done all you said, to no avail. Firefox is up to date for my OS, Can't access Bluesky on Safari either - it won't load.

I checked in my Bluesky #Feeds, and did a search on “r.countGraphemes” and there are numerous posts in the last 24 hours with the same problem as I reported above. The most recent one was a fix posted yesterday (URL= https://bsky.app/profile/2nb.bsky.social/post/3m7lhv7mwk22k). It is a fix for the same Firefox, but on Windows 7 (not for Mac OS 10.14.6), and I don't no how to implement such a ‘Github’ fix. I have also copied the fix to a TextEdit file, and attach it herewith as a jpeg.

I hope this gives some enlightenment to the problem, and that you can advise me further, the best course of action.

That's interesting! The script at the link says:

// add a dummy intl.segmenter impl
// there is a polyfill on the site but its broken [2025-12-09]

This is a script that can be applied to pages using one of the following extensions on Firefox across different operating systems:

• https://addons.mozilla.org/firefox/addon/tampermonkey/
• https://addons.mozilla.org/firefox/addon/violentmonkey/

Will either of those install on your version of Firefox?

Thanks jscher2000,

Installed add-on tampermonkey and it seems to have resolved the problem. I must say, however, that I am a complete novice when it comes to such add-ons, and their scripts etc.

Anyway, it appears problem solved.

Many thanks.