The read-only DataTransferItemList.length property returns the number of items in the list. If the list has no items, or is disabled (because it has no data store at all), this property returns zero.
The DataTransferItemList.remove() method removes the DataTransferItem at the specified index from the list. If the index is less than zero or greater than one less than the length of the list, the list will not be changed.
This property indicates whether the window is displayed in full screen mode or not. It is only reliable in Gecko 1.9 (Firefox 3) and later, see the Notes below.