onBeforeDrop

fires before a dragged element is released over the droppable area

boolean onBeforeDrop(object context,Event native_event);

context	object	the drag-n-drop context
native_event	Event	an HTML event object

boolean

returning false will prevent further drag-and-drop processing

Example

$$("editor").attachEvent("onBeforeDrop", function(context, native_event){
    //... some code here ... 
    // return false to block operation
    return true;
});

Details

The drag-and-drop context can have the following properties:

from - the source object
to - the target object
source - the ID of the dragged item
target - the ID of the drop target, null for drop on empty space
start - the ID from which drag-n-drop was started.