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.mozGetDataAt() method is used to retrieve an item in the drag event's data transfer object, based on a given format and index. This method returns null if the specified item does not exist or if the index is not in the range from zero to the number of items minus one.

Note: This method is Gecko-specific.


nsIVariant dataTransfer.mozGetDataAt([type], index);


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

Return value

The data item requested. If the specified item does not exist, null is returned.


This example shows the use of the mozGetDataAt() method in a drop event handler.

function drop_handler(event)
  var dt = event.dataTransfer;
  var count = dt.mozItemCount;
  output("Items: " + count + "\n");

  for (var i = 0; i < count; i++) {
    output(" Item " + i + ":\n");
    var types = dt.mozTypesAt(i);
    for (var t = 0; t < types.length; t++) {
      output("  " + types[t] + ": "); 
      try {
        var data = dt.mozGetDataAt(types[t], i); 
        output("(" + (typeof data) + ") : <" + data + " >\n");
      } catch (ex) {


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


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API drag and drop Method Non-standard Reference