[Nlk]

Где то ошибся?

document.addEventListener("scroll", myFunction);
var lastScrolled = 1;
function myFunction() {
    var scrolled = window.pageYOffset || document.documentElement.scrollTop;
	var scrolledThis = this.scrolled;
	if (scrolledThis < lastScrolled) {
		alert("TOP");
	} else {
		alert("BOTTOM");
	}
	lastScrolled = scrolledThis;
}