I was on the same route as you (in arts) however, recently I switched to Computer Science and math and took arts as extracurricular instead. If you really want to be good at programming it is probably best to take programming classes because it forces you to focus and learn faster. Hacking by yourself might be fun with no pressure, but you will need to fill a lot of gaps all by yourself (unless you have been hacking for a long time, you probably don't even need a cs degree). Then again, since you want to do web application, it doesn't need a lot of the theory that a cs degree demands. So you might want to see if your school offers programming intensive classes and try those. The reason I switched is because my school restrict arts students from taking math and cs courses (plus I didn't enjoy arts courses very much). If your school has no such restriction you can probably consider taking lots of programming classes.