Why is this AddEventListener Method not working

Question

It's working on the browser on my laptop perfectly well, i just posted it here and it's not working the way it should... 🙁
https://code.sololearn.com/WW45pvtdrJ6M/?ref=app
https://code.sololearn.com/WW45pvtdrJ6M/?ref=app

Answer 1

Its because sololearn loads the javascript before the page is fully loaded so you just need to wrap your code in a window.onload = function (){ (all the code) }

Answer 2

Thanks Mike