fx.Scroll = Class.create();
    fx.Scroll.prototype = Object.extend(new fx.Base(), {
    initialize: function(options) {
        this.setOptions(options);
    },

    scrollTo: function(el){
        var desty = Position.cumulativeOffset($(el));
        var dest = desty[1];
        var client = window.innerHeight || document.documentElement.clientHeight;
        var full = document.documentElement.scrollHeight;
        var top = window.pageYOffset || document.body.scrollTop || document.documentElement.scrollTop;
        if (dest+client > full) this.custom(top, dest - client + (full-dest));
        else this.custom(top, dest);
    },

    increase: function(){
        window.scrollTo(0, this.now);
    }
});

var Position = {
  cumulativeOffset: function(element) {
    var valueT = 0, valueL = 0;
    do {
      valueT += element.offsetTop  || 0;
      valueL += element.offsetLeft || 0;
      element = element.offsetParent;
    } while (element);
    return [valueL, valueT];
  }
}