let initialYOffset = window.pageYOffset;
let parallaxContainers = document.querySelectorAll('.parallax');
window.addEventListener('scroll', function (event) {
if (window.pageYOffset > initialYOffset) { // При скролле вниз
parallaxContainers.forEach(function (item) {
let currentBackgroundPos = item.style.backgroundPositionY;
if (currentBackgroundPos) {
if (parseInt(currentBackgroundPos) > -50) {
item.style.backgroundPositionY = (parseInt(currentBackgroundPos) - 2) + 'px';
}
} else {
item.style.backgroundPositionY = '0px';
}
});
} else { // При скролле вверх
parallaxContainers.forEach(function (item) {
let currentBackgroundPos = item.style.backgroundPositionY;
if (parseInt(currentBackgroundPos) != 0) {
item.style.backgroundPositionY = (parseInt(currentBackgroundPos) + 2) + 'px';
}
});
}
initialYOffset = window.pageYOffset;
});