js 触屏滚动

document.addEventListener('DOMContentLoaded', function() {
    var scrollButton = document.getElementById('scrollToTopButton');
    scrollButton.addEventListener('click', smoothScrollToTop, false);

    function smoothScrollToTop() {
        var currentY = window.scrollY;
        var distance = -currentY;
        var duration = 500; // 滚动持续时间，单位毫秒
        var startTime = null;

        function animation(currentTime) {
            if (startTime === null) startTime = currentTime;
            var timeElapsed = currentTime - startTime;
            var run = ease(timeElapsed, currentY, distance, duration);
            window.scrollTo(0, run);
            if (timeElapsed < duration) requestAnimationFrame(animation);
        }

        function ease(t, b, c, d) {
            t /= d / 2;
            if (t < 1) return c / 2 * t * t + b;
            t--;
            return -c / 2 * (t * (t - 2) - 1) + b;
        }

        requestAnimationFrame(animation);
    }
});