Error in the code.

Question

Hello everybody. I've written a code for scientific notation. I've tested it and it works for sure. But when i uploaded it to SoloLearn it stopped working for some reason. Could someone check it out and tell me a reason why it doesn't work?
https://code.sololearn.com/WaYsYeWzDgKM/?ref=app

Answer 1

Oh, thx, got it

Answer 2

On SoloLearn your JavaScript is started prior to your DOM being loaded so both variables on line 1 & 2 of JS are null.
https://code.sololearn.com/WunKLKcRfSag