Why is the for loop not working ?

Question

I wrote a code for ceasers cipher and everything looks perfect but for loop is not working. Though it is not showing any error in console, yet the code is not working.
And please check the window onload function also.

https://code.sololearn.com/Wqzhttr3J6ef/#html

Answer 1

https://code.sololearn.com/W0l8Z4uxBLn1/?ref=app

here there were some errors in your js...