Get Selected Nodes Get Current Node
Huge Data Tree This demo show performance of a tree with 10,000 node loaded in one time.
You can expand/collapse and check/uncheked nodes to see how quickly it response.
Get Checked Nodes The following lines show how to get checked nodes. 
          $("#showchecked").click(function(e){
                var s=$("#tree").getCheckedNodes();
                if(s !=null)
                alert(s.join(","));
                else
                alert("NULL");
            });
Get Current Node The following lines show how to get current node. 
            $("#showcurrent").click(function(e){
                var s=$("#tree").getCurrentNode();
                if(s !=null)
                    alert(s.text);
                else
                    alert("Current node is nothing");
             });