用 Javascript 实现锚点(Anchor)间平滑跳转

<SCRIPT type=text/javascript>

// 说明 :用 Javascript 实现锚点(Anchor)间平滑跳转
// 来源 :ThickBox 2.1
// 整理 :Yanfu Xie [xieyanfu@yahoo.com.cn]
// 网址 :http://www.codebit.cn
// 日期 :07.01.17

// 转换为数字
function intval(v)
{
    v = parseInt(v);
    return isNaN(v) ? 0 : v;
}

// 获取元素信息
function getPos(e)
{
    var l = 0;
    var t  = 0;
    var w = intval(e.style.width);
    var h = intval(e.style.height);
    var wb = e.offsetWidth;
    var hb = e.offsetHeight;
    while (e.offsetParent){
        l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):0);
        t += e.offsetTop  + (e.currentStyle?intval(e.currentStyle.borderTopWidth):0);
        e = e.offsetParent;
    }
    l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):0);
    t  += e.offsetTop  + (e.currentStyle?intval(e.currentStyle.borderTopWidth):0);
    return {x:l, y:t, w:w, h:h, wb:wb, hb:hb};
}

// 获取滚动条信息
function getScroll()  
{
    var t, l, w, h;
     
    if (document.documentElement && document.documentElement.scrollTop) {
        t = document.documentElement.scrollTop;
        l = document.documentElement.scrollLeft;
        w = document.documentElement.scrollWidth;
        h = document.documentElement.scrollHeight;
    } else if (document.body) {
        t = document.body.scrollTop;
        l = document.body.scrollLeft;
        w = document.body.scrollWidth;
        h = document.body.scrollHeight;
    }
    return { t: t, l: l, w: w, h: h };
}

// 锚点(Anchor)间平滑跳转
function scroller(el, duration)
{
    if(typeof el !='object') { el = document.getElementById(el); }

    if(!el) return;

    var z = this;
    z.el = el;
    z.p = getPos(el);
    z.s = getScroll();
    z.clear = function(){window.clearInterval(z.timer);z.timer=null};
    z.t=(new Date).getTime();

    z.step = function(){
        var t = (new Date).getTime();
        var p = (t - z.t) / duration;
        if (t >= duration + z.t) {
            z.clear();
            window.setTimeout(function(){z.scroll(z.p.y, z.p.x)},13);
        } else {
            st = ((-Math.cos(p*Math.PI)/2) + 0.5) * (z.p.y-z.s.t) + z.s.t;
            sl = ((-Math.cos(p*Math.PI)/2) + 0.5) * (z.p.x-z.s.l) + z.s.l;
            z.scroll(st, sl);
        }
    };
    z.scroll = function (t, l){window.scrollTo(l, t)};
    z.timer = window.setInterval(function(){z.step();},13);
}

</SCRIPT>

<STYLE type=text/css>
div.test {
    width:400px;
    margin:5px auto;
    border:1px solid #ccc;
}
div.test strong {
    font-size:16px;
    background:#fff;
    border-bottom:1px solid #aaa;
    margin:0;
    display:block;
    padding:5px 0;
    text-decoration:underline;
    color:#059B9A;
    cursor:pointer;
}
div.test p {
    height:400px;
    background:#f1f1f1;
    margin:0;
}

</STYLE>
调用方法:

scroller(el, duration)

el : 目标锚点 ID
duration : 持续时间,以毫秒为单位,越小越快,不能带引号哦int型
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