I know dear, I just wanted to point out, something in the JS code would causes the jump. I’m not telling you don’t use JS< but when you comment the JS and if problem is gone, so it tells you make you sure something JS part should be changed. Just for debugging.
By default, browser doesn’t focus on any element. As I asked you to explain a little about your
#part2 section of your JS, so we would find the issue.
Also try to remove the
tabindex from your input, and check if it works.
Maybe this could be becasue of bootstrap you added!
Another possible issue could be when an image is trying to load, and it fails, so the bound it could get will be less and causes issues for layout, not sure if it’s works for you or not.
This is really weird, I wish I could help you better. But indeed if I find the issue I will point out.
I also suggest, since you are good about UI, and layouting, start a new page without bootstrap(fact: dependency makes the work more fragile, and more harder to fix issues)