getCheckedNodesReturns: Array

    
 <button id="btnGet" class="gj-button-md">Get Checked Nodes</button>
 <div id="tree"></div>
 <script>
     var tree = $('#tree').tree({
         dataSource: '/Locations/Get',
         checkboxes: true
     });
     $('#btnGet').on('click', function() {
         var result = tree.getCheckedNodes();
         alert(result.join());
     });
 </script>