ActivationChanging Property (DataTreeClientEvents)

// The client event 'ActivationChanging' takes two parameters sender and e
// sender  is the object which is raising the event
// e is the DataTreeActivationEventArgs

function WebDataTree_ActivationChanging(sender, e) {
    //Gets the new active Node object
    var newActiveNode = e.getNewActiveNode();

    //Gets the text of the new active node
    var newNodeText = newActiveNode.get_text();

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