Javascript 实现锚点(Anchor)间平滑跳转

 (function($){
     $.fn.scroller = function(options){
         var defaultVal = {
             duration:
         };
         var obj = $.extend({},defaultVal,options);
         var el = options.el;
         var duration = options.duration;
         return this.each(function(){
             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)},);
                 } else {
                 st = ((-Math.cos(p*Math.PI)/) + 0.5) * (z.p.y-z.s.t) + z.s.t;
                 sl = ((-Math.cos(p*Math.PI)/) + 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();},);
             });
     };

     function intval(v)
     {
         v = parseInt(v);
         return isNaN(v) ?  : v;
     }

     // 获取元素信息
     function getPos(e)
     {
         var l = ;
         var t  = ;
         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):);
             t += e.offsetTop  + (e.currentStyle?intval(e.currentStyle.borderTopWidth):);
             e = e.offsetParent;
         }
         l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):);
         t  += e.offsetTop  + (e.currentStyle?intval(e.currentStyle.borderTopWidth):);
         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 };
     }
 })(jQuery)

 $(function(){
     $('#goto').click(function(){
         $(this).scroller(
             {
                 el:'t1',
                 duration:
             }
         );
     });
 })