bug on upload empty file on back button fixed sometimes, when the back button is pushed, an empty file is sent to 'do_upload.php', this resulted in the deletion of all wijzigingen
bug on upload empty file on back button fixed
sometimes, when the back button is pushed, an empty file is sent
to 'do_upload.php', this resulted in the deletion of all wijzigingen

now, the upload of an empty file is ignored (with an error in the log)

ko3st/zermelo-web,ko3st/zermelo-web,rsnel/ez-roosterbord,rsnel/ez-roosterbord