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

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

Related samples

Using Events for Customizing Drag-and-Drop

Details

If you drag multiple items, the event will be called once for the entire batch of items.

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(s)
target - the ID of the drop target, null for drop on empty space
start - the ID from which drag-n-drop was started
index - (number) the index of the node within the branch
parent - (string,number) the ID of the branch
x_offset - the left offset between the pointer and the dragged element
y_offset - the top offset between the pointer and the dragged element