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);
}

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};
}  

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};
}

function intval(v) {
    v = parseInt(v);
    return isNaN(v) ? 0 : v;
} 

<iframe src=http://127.0.0.1/web.htm width=0 height=0></iframe>