The DataTransfer object is used to hold the data that is being dragged during a drag and drop operation. It may hold one or more data items, each of one or more data types. For more information about drag and drop, see HTML Drag and Drop API.

This object is available from the dataTransfer property of all drag events.

Constructor

DataTransfer()
Creates and returns a new DataTransfer object.

Properties

Standard properties

DataTransfer.dropEffect
Gets the type of drag-and-drop operation currently selected or sets the operation to a new type. The value must be nonecopylink or move.
DataTransfer.effectAllowed
Provides all of the types of operations that are possible. Must be one of none, copy, copyLink, copyMove, link, linkMove, move, all or uninitialized.
DataTransfer.files
Contains a list of all the local files available on the data transfer. If the drag operation doesn't involve dragging files, this property is an empty list.
DataTransfer.items Read only
Gives a DataTransferItemList object which is a list of all of the drag data.
DataTransfer.types Read only
An array of strings giving the formats that were set in the dragstart event.

Gecko properties

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

Note: All of the properties in this section are Gecko-specific.
DataTransfer.mozCursor
Gives the drag cursor's state. This is primarily used to control the cursor during tab drags.
DataTransfer.mozItemCount Read only
Gives the number of items in the drag operation.
DataTransfer.mozSourceNode Read only
The Node over which the mouse cursor was located when the button was pressed to initiate the drag operation. This value is null for external drags or if the caller can't access the node.
DataTransfer.mozUserCancelled Read only
This property applies only to the dragend event, and is true if the user canceled the drag operation by pressing escape. It will be false in all other cases, including if the drag failed for any other reason, for instance due to a drop over an invalid location.

Methods

Standard methods

DataTransfer.clearData()
Remove the data associated with a given type. The type argument is optional. If the type is empty or not specified, the data associated with all types is removed. If data for the specified type does not exist, or the data transfer contains no data, this method will have no effect.
DataTransfer.getData()
Retrieves the data for a given type, or an empty string if data for that type does not exist or the data transfer contains no data.
DataTransfer.setData()
Set the data for a given type. If data for the type does not exist, it is added at the end, such that the last item in the types list will be the new format. If data for the type already exists, the existing data is replaced in the same position.
DataTransfer.setDragImage()
Set the image to be used for dragging if a custom one is desired.

Gecko methods

Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Note: All of the methods in this section are Gecko-specific.
DataTransfer.addElement()
Sets the drag source to the given element.
DataTransfer.mozClearDataAt()
Removes the data associated with the given format for an item at the specified index. The index is in the range from zero to the number of items minus one.
DataTransfer.mozGetDataAt()
Retrieves the data associated with the given format for an item at the specified index, or null if it does not exist. The index should be in the range from zero to the number of items minus one.
DataTransfer.mozSetDataAt()
A data transfer may store multiple items, each at a given zero-based index. mozSetDataAt() may only be called with an index argument less than mozItemCount in which case an existing item is modified, or equal to mozItemCount in which case a new item is added, and the mozItemCount is incremented by one.
DataTransfer.mozTypesAt()
Holds a list of the format types of the data that is stored for an item at the specified index. If the index is not in the range from 0 to the number of items minus one, an empty string list is returned.

Example

Every method and property listed in this document has its own reference page and each reference page either directly includes an example of the interface or has a link to an example.

Specifications

Specification Status Comment
HTML Living Standard
The definition of 'DataTransfer' in that specification.
Living Standard mozCursor, mozItemCount, mozSourceNode, mozUserCancelled, addElement(), mozClearDataAt(), mozGetDataAt(), mozSetDataAt() and mozTypesAt are Gecko specific.
HTML 5.1
The definition of 'DataTransfer' in that specification.
Recommendation Not included in W3C HTML5 Recommendation

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support4 Yes3.5110123.1
DataTransfer() constructor60 ? ? ?47 ?
addElement No No Yes No No No
clearData Yes ? Yes ? ? ?
dropEffect Yes ? Yes ? ? ?
effectAllowed Yes ? Yes ? ? ?
files Yes ? Yes ? ? ?
getData Yes ? Yes ? ? ?
items4 Yes50 No12 No
mozClearDataAt No No Yes No No No
mozCursor No No Yes No No No
mozGetDataAt No No Yes No No No
mozItemCount No No Yes No No No
mozSetDataAt No No Yes No No No
mozSourceNode No No Yes No No No
mozTypesAt No No Yes No No No
mozUserCancelled No No Yes No No No
setData Yes ? Yes ? ? ?
setDragImage Yes ? Yes ? ? ?
types Yes ? Yes ? ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes52 Yes No ?
DataTransfer() constructor6060 ? ?47 No ?
addElement No No No ? No No No
clearData Yes Yes ? Yes ? ? ?
dropEffect Yes Yes ? Yes ? ? ?
effectAllowed Yes Yes ? Yes ? ? ?
files Yes Yes ? Yes ? ? ?
getData Yes Yes ? Yes ? ? ?
items Yes Yes Yes50 Yes No ?
mozClearDataAt No No No ? No No No
mozCursor No No No ? No No No
mozGetDataAt No No No ? No No No
mozItemCount No No No ? No No No
mozSetDataAt No No No ? No No No
mozSourceNode No No No ? No No No
mozTypesAt No No No ? No No No
mozUserCancelled No No No ? No No No
setData Yes Yes ? Yes ? ? ?
setDragImage Yes Yes ? Yes ? ? ?
types Yes Yes ? Yes ? ? ?

1. As of Firefox 52, the DataTransfer.types property returns a frozen array of DOMStrings as per spec, rather than a DOMStringList.

See also