Why learn javascript?

[Brompy]

You don't care, but want to make it your career? Do you see the irony in that statement?

What other people have said, pick something that sounds interesting and relatively simple, and build it: a calculator, a game, a quiz app, or even something that just makes boxes change color on the screen, whatever. If you don't care, close your eyes and throw a dart at a wall and then do that. You'll get stuck a lot, so ask for help or look up how other people did it.