object ('a)
  method onabort :
    ('a Js.t, 'a File.progressEvent Js.t) Dom.event_listener
    Js.writeonly_prop
  method onerror :
    ('a Js.t, 'a File.progressEvent Js.t) Dom.event_listener
    Js.writeonly_prop
  method onload :
    ('a Js.t, 'a File.progressEvent Js.t) Dom.event_listener
    Js.writeonly_prop
  method onloadend :
    ('a Js.t, 'a File.progressEvent Js.t) Dom.event_listener
    Js.writeonly_prop
  method onloadstart :
    ('a Js.t, 'a File.progressEvent Js.t) Dom.event_listener
    Js.writeonly_prop
  method onprogress :
    ('a Js.t, 'a File.progressEvent Js.t) Dom.event_listener
    Js.writeonly_prop
end