js判断屏幕上下滚动事件

let lastScrollTop = 0;

window.addEventListener('scroll', function(event) {
    let st = window.pageYOffset || document.documentElement.scrollTop; // 获取当前滚动位置
    if (st > lastScrollTop){
        console.log('向下滚动');
    } else {
        console.log('向上滚动');
    }
    lastScrollTop = st <= 0 ? 0 : st; // 更新上一次的滚动位置
});

function throttle(func, wait) {
    let timeout = null;
    return function() {
        if (!timeout) {
            timeout = setTimeout(() => {
                func.apply(this, arguments);
                timeout = null;
            }, wait);
        }
    };
}

window.addEventListener('scroll', throttle(function(event) {
    // 滚动处理逻辑
}, 100)); // 设置节流时间为100毫秒