This page tests possible ways of copying file data between web page and a local system without server interaction.

read

Read local file using variant of File API. [https://developer.mozilla.org/En/NsIDOMFile] [File API (draft)]

Works on Firefox 3+

Show open dialog from javascript:

Firefox does not support click() method on input[type=file] [Mozilla bug 36619], nor label for click routing (they call it insecure, but don't understand why). Same in Opera. Well known opacity:0 hack must be used: [quirksmode.org, Styling an input type="file"]
open file

    write

    Save using data: URL.[RFC 2397]

    Save hello.zip.

    Problem 1: No way to specify filename.

    Problem 2: No way to force saving. View is the default.

    Can be initiated from javascript by assigning location.href property:

      drop

      Dragging file to the page.[whatwg.org, HTML5, Drag and Drop]
      Works on Firefox 3.5
      No browser supports dragging a file from a page, AFAIK.
        Your browser:
        ~jb