Undo a javascript function

I had an issue with a tabbed content page scrolling on its own on reload or when selecting different paged tabs so i tried adding

window.onbeforeunload = function () {
window.scrollTo(0,0);

It worked great, but i lost animations on some elements on different pages

How can i undo the before mentioned function and add this script only to a specific page?
I don’t remember if i added the script to “Scripts (for the head element)” or
“Scripts (end of the body tag):” or both in scripts and styles plugin.
Thanks!