// 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);
}