Déterminer le sens du scroll (up or down)

var scrollText = document.getElementById('scroll');
var lastScrollTop = 0;
var ticking = false;

function handleScroll() {
    var st = window.scrollY || document.documentElement.scrollTop;
    if (st > lastScrollTop) {
        scrollText.innerText = 'Scroll Down';
    } else {
        scrollText.innerText = 'Scroll Up';
    }
    lastScrollTop = Math.max(st, 0); // Éviter des valeurs négatives pour le scroll
}

window.addEventListener("scroll", function() {
    if (!ticking) {
        window.requestAnimationFrame(function() {
            handleScroll();
            ticking = false;
        });
        ticking = true;
    }
});