getElementById().innerHTML doesn’t work...

Question

When I try to output something using the method document.getElementById().innerHTML I only get an error message. What’s wrong with my code?
https://code.sololearn.com/WXElTLe26qiw/?ref=app

Answer 1

The DOM isn't ready yet, so you were trying to change a paragraph's content before the paragraph element was created/rendered by browser.

Wrap such code inside an onload event handler function as follows:

window.onload=function(){
document.getElementById("demo").innerHTML = "This is a paragraph.";
}

Hth, cmiiw