Why is the playground ignoring my JS?

Question

http://www.sololearn.com/app/html/playground/W4n3btgI1GU8/

Answer 1

Try to recheck your code as it's showing an error "Up2 not defined".

Answer 2

I found the error & solved it too. Now your code is working 100% correctly. Check it here:
https://code.sololearn.com/WlGKW6Vca1Q5/?ref=app

Answer 3

I checked it several times, it doesn't work even known there IS a function called Up() and a function called Up2()!