我正在寻找一个简单的,跨浏览器“滚动到顶部”的动画,我可以应用到一个链接。我不想需要一个JS库,如jQuery/Moo等。

// jQuery Equivilant to convert to pure JS...
$('html, body').animate({scrollTop:0}, 400);

对于那些在跳进图书馆之前应该100%学习JS的人来说,我是一个完美的例子。:(


当前回答

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”。

其他回答

一件容易的事。

var scrollIt = function(time) {
    // time = scroll time in ms
    var start = new Date().getTime(),
        scroll = document.documentElement.scrollTop + document.body.scrollTop,
        timer = setInterval(function() {
            var now = Math.min(time,(new Date().getTime())-start)/time;
            document.documentElement.scrollTop
                = document.body.scrollTop = (1-time)/start*scroll;
            if( now == 1) clearTimeout(timer);
        },25);
}
function scrollTo(element, to, duration) {
    if (duration <= 0) return;
    var difference = to - element.scrollTop;
    var perTick = difference / duration * 10;

    setTimeout(function() {
        element.scrollTop = element.scrollTop + perTick;
        if (element.scrollTop === to) return;
        scrollTo(element, to, duration - 10);
    }, 10);
}

演示:

function runScroll() { scrollTo(document.body, 0, 600); } var scrollme; scrollme = document.querySelector("#scrollme"); scrollme.addEventListener("click",runScroll,false) function scrollTo(element, to, duration) { if (duration <= 0) return; var difference = to - element.scrollTop; var perTick = difference / duration * 10; setTimeout(function() { element.scrollTop = element.scrollTop + perTick; if (element.scrollTop == to) return; scrollTo(element, to, duration - 10); }, 10); } <p>Very long page.Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. 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Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page.Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. Very long page. 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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');

平滑滚动现在在所有现代浏览器中都是默认实现的。 您还可以对其进行填充,以获得旧浏览器的支持。

// Scroll to specific values
// scrollTo is the same
window.scroll({
  top: 2500, 
  left: 0, 
  behavior: 'smooth'
});

// Scroll certain amounts from current position 
window.scrollBy({ 
  top: 100, // could be negative value
  left: 0, 
  behavior: 'smooth' 
});

// Scroll to a certain element
document.querySelector('.hello').scrollIntoView({ 
  behavior: 'smooth' 
});

// Scroll certain amounts from current position for any element
document.querySelector('.scrollable-element').scrollBy({
  top: 100, 
  behavior: 'smooth'
});

// Scroll to top
var element = document.querySelector('.scrollable-element');
element.scrollBy({
  top: -element.scrollTop, 
  behavior: 'smooth'
});

来源:https://css-tricks.com/snippets/jquery/smooth-scrolling/

我已经选择了@timwolla answer的@akai版本,并添加了stopAnimation函数作为返回,所以在开始新的动画之前,旧的动画可以停止。

if ( this.stopAnimation )
    this.stopAnimation()

    this.stopAnimation = scrollTo( el, scrollDestination, 300 )


// definitions

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

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

    animateScroll(0);

    return stopAnimation

    function stopAnimation() {
        clearTimeout( timeOut )
    }
}

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;
}