The Flash feature will use a SWF to upload in non-HTML5 browsers. All other browsers will use the HTML5 plugin,
force="flash" is used, then Flash will be used in all browsers.
is provided because Flash has some features that HTML5 does not yet have. But it is still not
recommended because of the many problems that Firefox and Webkit have with the Flash plugin.
When HTML5 feature is in use, drag & drop of files to the fieldset is supported.