Это старая версия документа!

Создание расширений для Firefox

https://developer.mozilla.org/En/DragDrop/Dragging_and_Dropping_Multiple_Items

function onDrop(event)
{
  var files = [];
  var dt = event.dataTransfer;
  for (var i = 0; i < dt.mozItemCount; dt++)
    files.push(dt.mozGetDataAt("application/x-moz-file", i));
}

https://developer.mozilla.org/En/DragDrop/Recommended_Drag_Types

http://mxr.mozilla.org/mozilla-central/source/toolkit/content/nsDragAndDrop.js

https://developer.mozilla.org/en/DragDrop/Drag_and_Drop