i tried on your too, same problem is the play left and right mode happens when the number to divide by is very big, i tested a 6 digit number
123456 and found a very minor bug.

input mode works fine!

if you fixed your http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1039.msg3858#msg3858, alert me i go study your codes and implement on this one with the scaffolds?

for ur info, so far, the school teachers used it did feedback some suggestions to improve this applet here but my friend is trying to fix it himself, to learn Ejs. it is interesting not everyone is into writing on forums, they prefer to read:)

when got time, i hint to him to post it on the forum for everyone to learn from:)