改编自下面的回答:

function scroll(y, duration) {

    var initialY = document.documentElement.scrollTop || document.body.scrollTop;
    var baseY = (initialY + y) * 0.5;
    var difference = initialY - baseY;
    var startTime = performance.now();

    function step() {
        var normalizedTime = (performance.now() - startTime) / duration;
        if (normalizedTime > 1) normalizedTime = 1;

        window.scrollTo(0, baseY + difference * Math.cos(normalizedTime * Math.PI));
        if (normalizedTime < 1) window.requestAnimationFrame(step);
    }
    window.requestAnimationFrame(step);
}

这应该允许你平滑地滚动(余弦函数)从任何地方到指定的“y”。

还有一种方法是使用window.scrollBy

JSFiddle

function scroll(pxPerFrame, duration) { if (!pxPerFrame || !duration) return; const end = new Date().getTime() + duration; step(); function step() { window.scrollBy(0, pxPerFrame); if (new Date().getTime() < end) { window.setTimeout(step, 1000 / 60); } else { console.log('done scrolling'); } } } body { width: 200px; } <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p> <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p> <p> <button onclick="scroll(-5, 3000)"> scroll(-5, 3000) </button> </p>

我修改了TimWolla的答案，使用二次输入-输出缓和(更流畅一点:)。下面是一个正在运行的示例:在jsFiddle上。这里提供了缓动函数:Robert Penner的缓动函数

document.getElementsByTagName('button')[0].onclick = function () {
    scrollTo(document.body, 0, 1250);   
}

function scrollTo(element, to, duration) {
    var start = element.scrollTop,
        change = to - start,
        increment = 20;

    var animateScroll = function(elapsedTime) {        
        elapsedTime += increment;
        var position = easeInOut(elapsedTime, start, change, duration);                        
        element.scrollTop = position; 
        if (elapsedTime < duration) {
            setTimeout(function() {
                animateScroll(elapsedTime);
            }, increment);
        }
    };

    animateScroll(0);
}

function easeInOut(currentTime, start, change, duration) {
    currentTime /= duration / 2;
    if (currentTime < 1) {
        return change / 2 * currentTime * currentTime + start;
    }
    currentTime -= 1;
    return -change / 2 * (currentTime * (currentTime - 2) - 1) + start;
}

基于这里的一些答案，但使用了一些简单的数学，使用正弦曲线进行平稳过渡:

scrollTo(element, from, to, duration, currentTime) {
       if (from <= 0) { from = 0;}
       if (to <= 0) { to = 0;}
       if (currentTime>=duration) return;
       let delta = to-from;
       let progress = currentTime / duration * Math.PI / 2;
       let position = delta * (Math.sin(progress));
       setTimeout(() => {
           element.scrollTop = from + position;
           this.scrollTo(element, from, to, duration, currentTime + 10);
       }, 10);
   }

用法:

// Smoothly scroll from current position to new position in 1/2 second.
scrollTo(element, element.scrollTop, element.scrollTop + 400, 500, 0);

注:注意ES6风格

看来已经有很多解决方案了。不管怎样，这是另一个，使用简化方程。

// first add raf shim
// http://www.paulirish.com/2011/requestanimationframe-for-smart-animating/
window.requestAnimFrame = (function(){
  return  window.requestAnimationFrame       ||
          window.webkitRequestAnimationFrame ||
          window.mozRequestAnimationFrame    ||
          function( callback ){
            window.setTimeout(callback, 1000 / 60);
          };
})();

// main function
function scrollToY(scrollTargetY, speed, easing) {
    // scrollTargetY: the target scrollY property of the window
    // speed: time in pixels per second
    // easing: easing equation to use

    var scrollY = window.scrollY || document.documentElement.scrollTop,
        scrollTargetY = scrollTargetY || 0,
        speed = speed || 2000,
        easing = easing || 'easeOutSine',
        currentTime = 0;

    // min time .1, max time .8 seconds
    var time = Math.max(.1, Math.min(Math.abs(scrollY - scrollTargetY) / speed, .8));

    // easing equations from https://github.com/danro/easing-js/blob/master/easing.js
    var easingEquations = {
            easeOutSine: function (pos) {
                return Math.sin(pos * (Math.PI / 2));
            },
            easeInOutSine: function (pos) {
                return (-0.5 * (Math.cos(Math.PI * pos) - 1));
            },
            easeInOutQuint: function (pos) {
                if ((pos /= 0.5) < 1) {
                    return 0.5 * Math.pow(pos, 5);
                }
                return 0.5 * (Math.pow((pos - 2), 5) + 2);
            }
        };

    // add animation loop
    function tick() {
        currentTime += 1 / 60;

        var p = currentTime / time;
        var t = easingEquations[easing](p);

        if (p < 1) {
            requestAnimFrame(tick);

            window.scrollTo(0, scrollY + ((scrollTargetY - scrollY) * t));
        } else {
            console.log('scroll done');
            window.scrollTo(0, scrollTargetY);
        }
    }

    // call it once to get started
    tick();
}

// scroll it!
scrollToY(0, 1500, 'easeInOutQuint');

没有人提到CSS属性滚动行为

CSS

html {
  scroll-behavior: smooth;
}

JS

window.scrollTo(0,0)