var Scroller=new Class({Implements:[Events,Options],options:{area:20,velocity:1,onChange:function(a,b){this.element.scrollTo(a,b)},fps:50},initialize:function(b,a){this.setOptions(a);this.element=document.id(b);this.listener=($type(this.element)!="element")?document.id(this.element.getDocument().body):this.element;this.timer=null;this.bound={attach:this.attach.bind(this),detach:this.detach.bind(this),getCoords:this.getCoords.bind(this)}},start:function(){this.listener.addEvents({mouseenter:this.bound.attach,mouseleave:this.bound.detach})},stop:function(){this.listener.removeEvents({mouseenter:this.bound.attach,mouseleave:this.bound.detach});this.timer=$clear(this.timer)},attach:function(){this.listener.addEvent("mousemove",this.bound.getCoords)},detach:function(){this.listener.removeEvent("mousemove",this.bound.getCoords);this.timer=$clear(this.timer)},getCoords:function(a){this.page=(this.listener.get("tag")=="body")?a.client:a.page;if(!this.timer){this.timer=this.scroll.periodical(Math.round(1000/this.options.fps),this)}},scroll:function(){var b=this.element.getSize(),a=this.element.getScroll(),f=this.element.getOffsets(),c=this.element.getScrollSize(),e={x:0,y:0};for(var d in this.page){if(this.page[d]<(this.options.area+f[d])&&a[d]!=0){e[d]=(this.page[d]-this.options.area-f[d])*this.options.velocity}else{if(this.page[d]+this.options.area>(b[d]+f[d])&&a[d]+b[d]!=c[d]){e[d]=(this.page[d]-b[d]+this.options.area-f[d])*this.options.velocity}}}if(e.y||e.x){this.fireEvent("change",[a.x+e.x,a.y+e.y])}}});