I have this in my Rails controller:

  def download_clip
    send_file "public/output.mp4", :type=>"video/mp4", :filename => "output.mp4", :disposition => 'attachment'
  end

and in my HTML code I have this:

<a href="download_clip/"></a>

Now could somebody tell me why Firefox's download window will NOT pou up, but chrome downloads the file fine? Instead firefox opens a new window and starts playing the file. I WANT THE DOWNLOAD BOX to POPUP. I have spend too much time on it