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");

             });