wc3edit.net

As Title says

Is it possible without using WE? If so with what?

The item ID could be read from WE, since it takes a lot of time starting up the WE, there are tools which can obtain rawcodes.
You can use RMPQEx to Extract rawcodes(Item ID in this case) , but they are in chunks then you can see a lot of unwanted information besides the object ID.
Hence you can use Haxorizer to clean the rawcode, to obtain Cleaned item id.

Apple wrote:The item ID could be read from WE, since it takes a lot of time starting up the WE, there are tools which can obtain rawcodes.
You can use RMPQEx to Extract rawcodes(Item ID in this case) , but they are in chunks then you can see a lot of unwanted information besides the object ID.
Hence you can use Haxorizer to clean the rawcode, to obtain Cleaned item id.

Alright, I've downloaded RMPQEx and Haxorizer, map already opened in RMPQEx
and now which txt should I extract, Item Data has .slk format by the way

EDIT: Turns out it's Units/ItemStrings. Now, I have picked the folder, the format changed to j, and haxorizer won't clean it, any ideas?

I can't seem to understand the problem you are having.
You have RMPQEx and you extracted the raw-data you want.
Now you can either read them yourself or use the cleaner provided in Haxoerizer.

In any way it should b a .txt file. Unless what you extracted is the war3map.j file which has nothing to do with your request.