KeyDown Property (DataMenuClientEvents)

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

        function WebDataMenu1_KeyDown(sender, e) {
        //Gets the DataMenuItem object that is going to be selected
        var Item = e.getItem();

        //Gets the text of the item
        var ItemText = Item.get_text();   
    if (!confirm("Are you sure you want to navigate from or select or unselect the item '"+ItemText+"'?"))
          //Cancels the KeyDown
         e.set_cancel(true);
    }