Javascript not working

I was using an FTP to update some files on my hosting site. After, I was no longer able to view my themes or edit them. Said that “themes.php” in my wp-admin folder had errors on various lines(I never touched the file though). I upgraded to WordPress 2.92. That allowed me to view my themes again. However, my previously installed theme was not there. I’ve uploaded it, and activated it, but the site isn’t showing the JavaScript now and only showing a really ugly html site. Any ideas why?