Newbie here trying to get an internship

what concepts should I need to clear to get a javascript internship. I use javascript for backend and need an internship for backend. but I wanna learn while I work on my internship. I have solidified a lot of concepts. I don't wanna get an internship at a big firm, but any moderate software house. So what concepts do interviews generally test the interns on? I wanna learn them ASAP before applying there https://vlc.onl/ !!!

I got this,...