This plugin uses XHR for uploading multiple files with progress-bar
in FF3.6+, Safari4+, Chrome and falls back to hidden iframe based upload
in other browsers, providing good user experience everywhere.
As a response to a reported bug where Chrome was taking ages to load
up a flash multiple-file uploader, I’ve updated KFM to use HTML5′s
multiple-file input box where possible.
Here is how you can implement drag and drop multiple file upload
with native JavaScript. No plugins needed. Just plain old new HTML5.
Again there is a working demo. You will need FireFox 3.6 to test it.
Full source code can be at GitHub.