验证使用Jeditable更改的值

I'm not quite good at javascript and ajax, so I ask you for help. I use Symfony2 and Twig and I have a field which I change with jediable but its value should be unique. So I check this in the controller action, but I can't succeed in making the app to act normally. I tried a lot of things and the closest to the result I want is this:I'm not quite good at javascript and ajax, so I