Why my addEventListener don't work?

Question

I want to do a button which will create a new div element.
https://code.sololearn.com/WMwPhmWVXVM7/?ref=app

Answer 1

Your addEventListener is fine. The problem is that your btn isn't what you think it is because you need to wait for the document to load before you can select elements.
/* Updated: used document instead of window because it's quicker */
document.addEventListener("DOMContentLoaded", () =>{
// now the document has loaded
// so, you can put your code here
})

Answer 2

Alek Levun You won't have this problem if you put all your JavaScript in a script tag in your HTML but then all your JavaScript would be in your HTML file and that in my opinion is a much bigger problem.

Answer 3

Thanks, i know about this problem, but i thought that i'll not have this problem in this aplikation. I'm styding on the laptop in vscode.

Answer 4

Based on some experimenting, I've discovered differences in load order in the way the SL App assembles the various bits on Android vs iOS vs browser.
https://code.sololearn.com/Wa16A20a6a23/?ref=app
Due to the nature of asynchronous file loading over HTTP and bizarre loading discrepancies on SL, it's a good idea to isolate DOM access to code that's guaranteed to execute after the DOM has loaded... as presented by CamelBeatsSnake.
On that note... his original answer should be marked as the correct answer. 😉👌