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   1  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.docBody=document.id(this.element.getDocument().body);this.listener=($type(this.element)!="element")?this.docBody:this.element;this.timer=null;this.bound={attach:this.attach.bind(this),detach:this.detach.bind(this),getCoords:this.getCoords.bind(this)}},start:function(){this.listener.addEvents({mouseenter:this.bound.attach,mouseleave:this.bound.detach})},stop:function(){this.listener.removeEvents({mouseenter:this.bound.attach,mouseleave:this.bound.detach});this.detach();this.timer=$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 c=this.element.getSize(),a=this.element.getScroll(),h=this.element!=this.docBody?this.element.getOffsets():{x:0,y:0},d=this.element.getScrollSize(),g={x:0,y:0},e=this.options.area.top||this.options.area,b=this.options.area.bottom||this.options.area;for(var f in this.page){if(this.page[f]<(e+h[f])&&a[f]!=0){g[f]=(this.page[f]-e-h[f])*this.options.velocity}else{if(this.page[f]+b>(c[f]+h[f])&&a[f]+c[f]!=d[f]){g[f]=(this.page[f]-c[f]+b-h[f])*this.options.velocity}}g[f]=g[f].round()}if(g.y||g.x){this.fireEvent("change",[a.x+g.x,a.y+g.y])}}});