The DataTransferItem object represents one drag data item. During a drag operation, each drag event has a dataTransfer property which contains a list of drag data items. Each item in the list is a DataTransferItem object.

API DataTransferItem drag and drop HTML DOM HTML Drag and Drop API Interface Reference

If the item is a file, the DataTransferItem.getAsFile() method returns the drag data item's File object. If the item is not a file, this method returns null.

API DataTransferItem drag and drop HTML DOM HTML Drag and Drop API Method Reference

The DataTransferItem.getAsString() method invokes the given callback with the drag data item's string data as the argument if the item's kind is a Plain unicode string (i.e. kind is string).

API DataTransferItem drag and drop getAsString HTML DOM HTML Drag and Drop API Method Reference

The read-only DataTransferItem.kind property returns a DataTransferItem representing the drag data item kind: some text or some file.

API DataTransferItem drag and drop HTML DOM HTML Drag and Drop API kind Property Reference

The read-only DataTransferItem.type property returns the type (format) of the DataTransferItem object representing the drag data item. The type is a Unicode string generally given by a MIME type, although a MIME type is not required.

API DataTransferItem drag and drop HTML DOM HTML Drag and Drop API Property Reference Type