NodeChecking プロパティ

// The client event 'NodeChecking' takes two parameters sender and e
    // sender  is the object which is raising the event
    // e is the DataTreeNodeEventArgs
    function WebDataTree_NodeChecking(sender, e) {

        //Gets the node object that is going to be checked
        var node = e.getNode();

        //Gets the text of the node
        var nodeText = node.get_text();

        if (!confirm("Are you sure you want to check the node '" + nodeText + "'?"))
        //Cancels the NodeChecking event
            e.set_cancel(true);
}