jquery dynatree plugin disabling child node only

Question

Can I disable the child nodes only in jquery dyna tree.

how would i do that` $(document).ready(function() { activeVisible: true, $("#tree").dynatree({ checkbox: true, persist: false, selectMode: 3, rootVisible: true, unselectable:true,

    onActivate: function(dtnode) {
        logMsg("onActivate(%o)", dtnode);
        $("#echoActive").text(dtnode.data.title);
        $("#echoActive2").text(dtnode.data.key);
        $('#ids').val($("#echoActive2").text());

        if (dtnode.data.url)
            window.open(dtnode.data.url);
    },



    onSelect: function(flag, dtnode) {
        // This will happen each time a check box is selected/deselected
        var selectedNodes = dtnode.tree.getSelectedNodes();
        var selectedKeys = $.map(selectedNodes, function(node) {
            return node.data.key;
        });
        // Set the hidden input field's value to the selected items
        $('#SelectedItems').val(selectedKeys.join(","));

        //                logMsg("onSelect(%o, %o)", dtnode);
        //              var s = dtnode.tree.getSelectedNodes().join(", ");
        //              $("#echoSelected").text(s);

    },

    checkbox: true

});


    // Remove all of the icons from the tree
    $('#tree .ui-dynatree-icon').remove();

    // Split out the items listed in the SelectedItems hidden input box
    var items = $('#SelectedItemss').val().split(',');
    var tree = $("#tree").dynatree("getTree");
    // Mark each of those items as selected in the tree
    for (var i = 0; i < items.length; i++) {
        var node = tree.getNodeByKey(items[i]);
        node.select(true);
        node.activate();

    }

});

// $(function() { // $("#Button1").click(function() { //
// $("#username_warning").append($("#Text1").val()); // }); // });

 $(document).ready(function() {
     $("#txt_username").blur(function() {
         var username_length;

         username_length = $("#txt_username").val().length;
         $("#username_warning").empty();

         if (username_length == 0)
             $("#username_warning").append("Please Enter a Valid Name");
   });


}); 

`