Laravel 5.4稀有反应

Question

I am facing problems with Laravel.

• i use AJAX to perform a product save, The first save indicates success.
  • {status: "SUCCESS"}
• The second one also save well but ajax goes to .fail method and this is the full response.
  • 1010910110{status: "SUCCESS"}

As you can see there is a number "1010910110" and i do not know where that number come from.

controller response:

return response()->json(['status' => 'SUCCESS']);