Always error when i click button

Question

I want to add numbers to the array every time I click the button and display the element array on the p element with id = "demo".
but instead an error 'occurred when I felt there was nothing wrong with my code, someone help me solve this error problem' and explain to me why this could happen.
https://code.sololearn.com/WFg82Ck9lSW9/?ref=app

Answer 1

I've debugged your code, here it is :
https://code.sololearn.com/W6QU3vsTWqBO/?ref=app

Answer 2

You wrote
1) object.innerHtml instead of object.innerHTML
2) your event Listener was defined in a bad way : instead of having like the following, you added a { as if all your function was an object : idBtn.addEventListener("click",function(){...})

Answer 3

geez I'm so careless 😥 Thank you very much for answering

Answer 4

LISANGOLA BONDJALI CHRISTIAN Is this because I didn't assign a value to variable a? But before that, thank you for answering my question

Answer 5

Juste see your code where you add the event listener, how the callback is defined