Why I receive property value eror?

Question

https://code.sololearn.com/WL69Q39t30xD/?ref=app

Answer 1

As soon as your page loaded you tried to get value of input field which is null (empty). You need to get value of input field only when you click a button, never before, that's why I used .value of input field with Button function

Answer 2

https://code.sololearn.com/W527RD7o3jW2/?ref=app

You tried to get value of input field immediately, even though it is empty (null)

Answer 3

i don't understand what you change in my code
can you explain!