So I understand that IE9 does not support the File API, which means that the file input element does not have a files property present on it. The FormData object also does not exist in IE9, so that can't be used to manually append together a set of fields into an upload. I've been pouring through the plugin code in real time and I still don't understand how it's doing it.
Does anyone know how or where exactly this plugin gains reference to or attaches the actual file content to its upload request in sans-File API IE9?