Why is there an error?

Question

https://code.sololearn.com/WOMCbKdUF5vz/?ref=app

Answer 1

window.onload = function(){
var sec = document.getElementsByTagName("section");
sec[0].innerHTML = "Hello";
}

Answer 2

U didn't place parentheses in your function..
And getElementsByTagName..
Its elements not element

Answer 3

window.onload = function{
var sec=document.getElementByTagName("section");
sec[0].innerHTML="Hello";
}