Math.easeInOutQuad = function(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 for Smart Animating http://goo.gl/sx5sts var requestAnimFrame = (function() { return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function(callback) { window.setTimeout(callback, 1000 / 60) } })() // because it's so fucking difficult to detect the scrolling element, just move them all function move(amount) { document.documentElement.scrollTop = amount document.body.parentNode.scrollTop = amount document.body.scrollTop = amount } function position() { return document.documentElement.scrollTop || document.body.parentNode.scrollTop || document.body.scrollTop } export function scrollTo(to, duration, callback) { const start = position() const change = to - start const increment = 20 let currentTime = 0 duration = (typeof (duration) === 'undefined') ? 500 : duration var animateScroll = function() { // increment the time currentTime += increment // find the value with the quadratic in-out easing function var val = Math.easeInOutQuad(currentTime, start, change, duration) // move the document.body move(val) // do the animation unless its over if (currentTime < duration) { requestAnimFrame(animateScroll) } else { if (callback && typeof (callback) === 'function') { // the animation is done so lets callback callback() } } } animateScroll() }