setTimeout() / setInterval() don't seem to be working

[tao-oat]

Hello,
I'm trying to run a script on a page that loads dynamically(?), so I have to wait quite a while for the element I want to be present.
Using setTimeout() or setInterval() has no effect whatsoever, as the script action runs instantly, regardless of the value I put in the timeout:
setTimeout(remove_elements('._3z9_h'), 5000);
or
setInterval(remove_elements('._3z9_h'), 5000);

Using the "load" event seems to delay it a bit, but it's not enough, as the page is only halfway through when it runs:
window.addEventListener('load', remove_elements('._3z9_h'));

Is it a bug or am I doing something wrong?