Unidentified error...

Question

Hi, I was writing one of my first web codes on SoloLearn. I had to use the document.getElementById() function but I am facing a problem...
This function actually returns a Null everytime I try it... I tried to find out what was wrong, and I looked at some other codes but I can't figure out what's the problem in what I wrote...
In advance, thanks for your help!
I join the code to this post :
https://code.sololearn.com/W03IwW64Q698/?ref=app

Answer 1

your code return null because you'd be calling the document before it was loaded,you need to wrap it in an window.onload function:

window.onload = function() {
var div = document.getElementById('myDiv');
alert(div);
};

Answer 2

Ok thanks for your answer! If I want to make a bigger code, does it need to be all wrapped into this function?
And is it a specification of SoloLearn or is it a function that I shall reuse in all my codes?
Thanks!