Event.observe(window,"load",function(){var a="";if(null==(a=Cookie.get("bg"))){a=BGs[$random(0,BGs.length-1)];Cookie.set("bg",a,0)}$E("body").setStyle({backgroundImage:"url("+a+")"})});function clearbg(){Cookie.erase("bg");null!=Cookie.get("bg")&&alert("remove failed")}