How can i add inner HTML under a specific Node

Question

I'm trying to learn scripting but im lost

I added Inner HTML under a Node using inspector tool as the below screenshot showing but i'm not sure how to make user script to keep the change after reload the page... Added Inner under node

Answer 1

Look here

as in example :

let p = document.createElement("p");
document.body.appendChild(p);

you can go too desire nest by

document.querySelector()

You can see that here

But to keep changes you have to make your own website and write that script in your's js file