Code Not Working

Question

I was trying to do a code using what I learned about DOM so far, and it's not working, the console is saying that the var with a element from HTML is null.
https://code.sololearn.com/WDtw9AtV56v0/?ref=app

Answer 1

1. Put your codes in window.onload

2. Demo:
https://code.sololearn.com/WgloMkSRQhmx/?ref=app

3. Explanation:
The codes in JS tab runs before the DOM exists. Because they are put inside head element when compiling.

4. Further explanation :
Another way to solve this is putting the scripts at end of body element.

5. This code by Calvin best demonstrates the sequence of execution :
https://code.sololearn.com/W8qiO41gHNfu/?ref=app

Answer 2

It seems to be working for me. Console is not returning any error.

Answer 3

Gordon hey, thank you! Really helped me