the simple ajax tooltip based on prototype --koma

On begining this code.you should add script reference that is"prototype.1.3"

        var tip = Class.create();
        tip.prototype={
            initialize:function(obj){
                this.main = obj;
                this.id = obj.id;
                this.main.onmouseover = this.showTip.bind(this);
                this.main.onmouseout = this.hideTip.bind(this);
            },
            showTip:function(){
                var div = document.createElement("div");
                div.style.width = "56px";
                div.style.backgroundColor = "#ff0066";
                div.style.height = "24px";
                div.style.position = "absolute";
                div.style.left = new Position.cumulativeOffset(this.main)[0]+55;
                div.style.top = new Position.cumulativeOffset(this.main)[1]+20;
                div.innerHTML = this.desc();
                div.id = this.id+"_";
                document.body.appendChild(div);
            },
            
            hideTip:function(){
                Element.remove(this.id+"_");
            },
            
            desc:function(){
                var result;
                var option = {
                parameters:"s=s",
                method:"get",
                onSuccess:function(transport){
                    var rp = transport.responseText;
                    result = rp;
                }
              };
              var ajax = new Ajax.Request("ajax.aspx",option);
              return result;
            }
        };
        
        window.onload=function(){
            var o = document.getElementById("bt");
            var tips = new tip(o);
        }