How to Disable Print Dialog on Firefox Browser

Annoying with print dialog?
Need to disable print dialog on your controlled environment?
Need to disable print dialog on your web based Point of Sale (POS) applications (e.g phppointofsale)?
Need to disable print dialog on your web based ticket printing applications?

1. Type about:config on address bar
2. Choose to promise
3. Right clicik and create new boolean
   “print.always_print_silent = true”
   “print.show_print_progress = false”

Done

Note: Make sure to set default printer to your desired printer and all parameter already configured