//-----平滑锚点函数开始-----
/*
scroller(el, duration)

el : 目标锚点 ID
duration : 持续时间，以毫秒为单位，越小越快
*/
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);
 } 
//-----平滑锚点函数END-----