Rails : ActionController::UnknownFormat when adding image in ajax

hi i am trying to upload a form via ajax , the form works fine when i send without a attachment but when i attach it gives ActionController::UnknownFormat , I am using activestorage migration for this

@items_list= Item.where(:category_id => params[:item][:category_id])
  respond_to do |f|
    f.js
  end```