So I decided to test the christld ones:

Twitter seems to work (brings up form).

Facebook redirects to an error.

Linkedin seems to work (brings up form when logged in).

Pinterest seems to work (brought up create board dialog when logged in)

Google+ seems to work (brings up share form).

I do have to say that for me that these would actually work and the JS likely wouldn't in some cases, since I make heavy use of Firefox's containers now to sandbox a lot of online identities, and just have new windows for certain URLs automatically load in the correct container.