While cleaning the inside of the windshield, I accidently dislodged the AM/FM antenna button from the windshield connection.

Looks like it was a soldered connection.

Can I use a dab of JB Weld to reattach it, or will it need to be re-soldered?

Thanks.

While cleaning the inside of the windshield, I accidently dislodged the AM/FM antenna button from the windshield connection.

Looks like it was a soldered connection.

Can I use a dab of JB Weld to reattach it, or will it need to be re-soldered?

Thanks.
I'd go to a windshield shop and have them reattach it. It shouldn't cost much at all.

It needs to be soldered or have a special conductive epoxy applied to reattach it. If you use JB weld, you might as well leave it unhooked.
I'd take it to a glass place and see what they can do for you.