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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.

The DataTransfer.mozClearDataAt() method removes the data associated with the given format for an item at the specified index. The index must be in the range from zero to the number of items minus one.

If the format argument is not provided, then the data associated with all formats is removed. If the format is not found, then this method has no effect. If the last format for the item is removed, the entire item is removed, reducing mozItemCount by one.

Removing the last format for a particular index removes that item entirely, shifting the remaining items down and changing their indices.

Note: This method is Gecko-specific.


void dataTransfer.mozClearDataAt([type], index);


A string representing the type of the drag data to remove from the drag data object.
A unsigned long representing the index of the data to remove.

Return value



This example shows the use of the mozClearDataAt() method in a dragend event handler.

function dragend_handler(event)
  var dt = event.dataTransfer;
  // Remove a text/html item
  dt.mozClearDataAt("text/html", 1);


This method is not defined in any Web standard.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
No support No support (Yes) No support No support No support
Feature Android Android Webview Chrome for Android Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile
Basic support No support No support No support ? ? No support No support No support

[1]Partial support refers to not supporting .setDragImage []

See also

Document Tags and Contributors

 Contributors to this page: rolfedh, AFBarstow
 Last updated by: rolfedh,