Не работает document.getElementById

Question

При вызове из внешнего файла не работает document.getElementById(id)
style.backgroundColor="red";

Answer 1

Let the HTML load first, so that you can work on it. Reference:
https://www.sololearn.com/learn/JavaScript/2758/

window.onload = function() {
...your code
}

As far as your objective is concerned, you might wanna alter the CSS for the change in its background color:

window.onload = function() {
document.getElementById("next").style.background="blue";
}

The innerHTML property would paste a text (blue) on your rectangle instead.

Answer 2

https://code.sololearn.com/Wuc05BfKInjC/?ref=app

Answer 3

thanks

Answer 4

if I place the code in html it's working

Answer 5

but if I place this code in external file it's not working