无需使用jQuery即可平滑滚动

尝试使用此平滑滚动演示或类似的算法：

1. 使用获取当前的最佳位置

   self.pageYOffset

2. 获取元素的位置，直到要滚动到的位置：

   element.offsetTop

3. 进行for循环到达该位置，这将非常快，或者使用计时器进行平滑滚动，直到使用

   window.scrollTo

安德鲁·约翰逊的原始代码：

function currentYPosition() {    // Firefox, Chrome, Opera, Safari    if (self.pageYOffset) return self.pageYOffset;    // Internet Explorer 6 - standards mode    if (document.documentElement && document.documentElement.scrollTop)        return document.documentElement.scrollTop;    // Internet Explorer 6, 7 and 8    if (document.body.scrollTop) return document.body.scrollTop;    return 0;}function elmYPosition(eID) {    var elm = document.getElementById(eID);    var y = elm.offsetTop;    var node = elm;    while (node.offsetParent && node.offsetParent != document.body) {        node = node.offsetParent;        y += node.offsetTop;    } return y;}function smoothScroll(eID) {    var startY = currentYPosition();    var stopY = elmYPosition(eID);    var distance = stopY > startY ? stopY - startY : startY - stopY;    if (distance < 100) {        scrollTo(0, stopY); return;    }    var speed = Math.round(distance / 100);    if (speed >= 20) speed = 20;    var step = Math.round(distance / 25);    var leapY = stopY > startY ? startY + step : startY - step;    var timer = 0;    if (stopY > startY) {        for ( var i=startY; i<stopY; i+=step ) { setTimeout("window.scrollTo(0, "+leapY+")", timer * speed); leapY += step; if (leapY > stopY) leapY = stopY; timer++;        } return;    }    for ( var i=startY; i>stopY; i-=step ) {        setTimeout("window.scrollTo(0, "+leapY+")", timer * speed);        leapY -= step; if (leapY < stopY) leapY = stopY; timer++;    }}