At protonet we’re working on bringing a rich file manager to the web that has a similar look and feel like the Windows Explorer or the Finder in OS X. An essential part of this is the experience of uploading files from the Desktop via drag & drop. There’s already a well supported HTML5 API available that allows such interactions.
The problem with this API is that it offers no solution on how to deal with folders. When a user drops a folder he expects it (and all contained files) to be uploaded.
How it’s working
Chrome v21 comes with a new method on the DataTransferItem object which returns the dropped file/folder as a file system entry. Using the file system api those entries can be accessed and traversed.
Here’s a simple script that recursively loops through all the dropped files and folders: