Cross browser JavaScript (not jQuery...) scroll to top animation

228

I'm looking for a simple, cross-browser "scroll to top" animation I can apply to a link. I don't want to require a JS library such as jQuery/Moo, etc.

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

I'm a perfect case for someone who should have learned JS 100% before jumping into a library. :(

This question is tagged with javascript

~ Asked on 2012-01-18 21:46:24

The Best Answer is


141

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);
}

Demo:

_x000D_
_x000D_
function runScroll() {_x000D_
  scrollTo(document.body, 0, 600);_x000D_
}_x000D_
var scrollme;_x000D_
scrollme = document.querySelector("#scrollme");_x000D_
scrollme.addEventListener("click",runScroll,false)_x000D_
_x000D_
function scrollTo(element, to, duration) {_x000D_
  if (duration <= 0) return;_x000D_
  var difference = to - element.scrollTop;_x000D_
  var perTick = difference / duration * 10;_x000D_
_x000D_
  setTimeout(function() {_x000D_
    element.scrollTop = element.scrollTop + perTick;_x000D_
    if (element.scrollTop == to) return;_x000D_
    scrollTo(element, to, duration - 10);_x000D_
  }, 10);_x000D_
}
_x000D_
<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. 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. 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. 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. 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. 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._x000D_
</p>_x000D_
<button id=scrollme type="button">To the top</button>
_x000D_
_x000D_
_x000D_

~ Answered on 2012-01-18 21:57:05


114

looks like there's a lot of solutions already. anyway, here's another one, uses easing equations..

// 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');

~ Answered on 2014-11-07 19:20:29


Most Viewed Questions: