Specifies the data, its format and the associated position for the current drag-and-drop operation.
Note: The dataTransfer object and its mozSetDataAt method are supported in Firefox from version 3.5.
The mozSetDataAt method is an extension of the setData method for dragging multiple items.
In Firefox, the modification of the dragged data is not allowed during the drag operation only at the start point of a drag operation.
That's why, the mozClearDataAt and mozSetDataAt methods can only be called in a handler for the ondragstart event.
The call to the mozClearDataAt and mozSetDataAt methods in other cases raises an exception.
Required. String that specifies the format of the data to assign.
In Firefox, the data format can be an arbitrary string.
If data for the specified format already exists, it is replaced with the new value.
If the specified data format does not exist yet, both new data and its format are added to the current data transfer.
Required. String that specifies the data to assign to the current data transfer.
Required. A zero-based integer that specifies the position of the item in the list of dragged items.
The value of the index parameter must be less or equal to the number of dragged items.
You can get the number of dragged items with the mozItemCount property.
If an item already exists at the specified position (the index parameter is less than the number of dragged items), the new data in its format is set for that item.
If the index parameter is equal to the number of dragged items, a new item is added to the end of the list of dragged items and the specified data in its format is set for that item.
If the index parameter is greater than the number of dragged items, the mozSetDataAt method raises an exception.