How to use JavaScript to redirect a page if a specific div class does not exist?

Question

I am trying to create a redirect if a specific div class does not exist in the HTML code of the page.

So far I've written the following code, but I guess now it's the "opposite way" (redirect if the div exists, not if it doesn't):

if (!document.getElementsByClassName("flickity-lazyloaded")[0]) {
window.location.href = "/404";}

How do I make it work the way I want?

FYI: The weird thing is that when I create a JSFiddle it works as expected - but on an actual website it redirects me despite the presence of the ".flickity-lazyloaded" class in the HTML: < ;/p>

https://jsfiddle.net/v97k5new/1/

Answer 1

if (!document.getElementsByClassName("flickity-lazyloaded")[0]) {
window.location.href = "https://stackoverflow.com"}

<div> hello </div>