Just a fun note: You can replace this f.addEventListener('keypress',e=>{...}) With the older but essentially equivalent f.onkeypress=e=>{...} and sa

Just a fun note: You can replace this f.addEventListener('keypress',e=>{...}) With the older but essentially equivalent f.onkeypress=e=>{...} and save 18 characters. You can even use `onkeyup` and save 3 more characters.