Did they damage that target? Disable it? Destroy it?

I haven't seen any public statistics for this, but based on my understanding, if you hit pretty much any modern tank on top hatch or some other weak spot with a javelin it'll at least disable the tank as it pretty much melts everything inside the crew space/engine bay. Those might be repairable, but most likely not in the location.

And what Ukrainians will most likely encounter is not a modern tank, but a T-62 or some even older soviet relic, which doesn't have active armor and those can be stopped with a good throw of molotov cocktail. So, my somewhat uneducated guess would be that every decent hit is a destroyed tank. Of course there's missed shots, less than optimal impacts and all that, so actual number isn't 100%, but I'd guess that it's not far off.

And for tanks there's also a guestion if Ukraine can even find anything to shoot at. On Ukrainian reports destroyed tanks have been in single digits per day for quite a while, so either Russia has learned on how to defend their gear or (in my opinion more likely) they just don't have that many tanks anymore. Obviously across the whole Russia there's a ton of relics around, starting from T-34's from WW1, but I guess no one knows how many of those are in condition where they could even move on their own and even if they did it's guestionable how effective those would be on todays battle field.

But javelins are still pretty neat hardware and they can easily destroy pretty much anything on the field, the only guestion is if Ukraine can get those close enough to hit anything interesting.

Oh yeah they work. Tbh I'd think you'd need some sort of TRPHY system to not make it a guaranteed kill when it hits. These are also way more valuable than the FSV drones as a lot of times they just disable and the crew has time to escape. Javelins are basically downward firing tank sabbots and when they hit, it melts everything inside. Depleting both material and trained personnel at the same time.