Find the full document at http://www.html5rocks.com/en/tutorials/file/dndfiles/
In each example you can also drag files to the 'choose' button and drop them.
Select files and see the 'name', 'filetype', 'filesize' and 'last modified'
Select some image file and they will be displayed as thumbnails
Select a text file and then choose the slice you want to view
Read bytes: