The nodeBeforeDropped event handler is called before a draggable node is dropped in another position. If the event handler returns false, the drop action will be prevented.

$(function () {
    // Set nodeBeforeDropped event handler function
    $(".selector").wijtree({
        nodeBeforeDropped : function (e, data) {
     
        }
    });
});

nodeBeforeDropped = function ( 
   e : jQuery.Event,
   data : object
) { };