How to Use HTML5 File Drag & Drop

Dragging and dropping files from your desktop to a browser is one of the ultimate goals for web application integration. This is the first in a four-part series of posts which describes how to:

1. enable file dragging and dropping onto a web page element
2. analyze dropped files in JavaScript
3. load and parse files on the client
4. asynchronously upload files to the server using XMLHttpRequest2
5. show a graphical progress bar while the upload occurs
6. use progressive enhancement to ensure your file upload form works in any browser (good news for all you IE6 fans!)
7. code it in plain ol’ JavaScript without a library.

http://www.sitepoint.com/html5-file-drag-and-drop/