Ajax request is executed but fails?

Question

AJAX

I have an ajax request

$.ajax({
            url: localDancerweek,
            type: "POST",
            headers: {
                "mapname": songCodename,
                "type": "write",
                "nickname": "",
                "avatar": "",
                "score": ""
            },
            dataType: "json"
        }).done(function()  {
            alert("Success.");
        }).fail(function(xhr, status, error)  {
            alert("Sorry. Server unavailable. " );
            alert( [ xhr.status, status, error ] );
        });

On successful request, a json file is created

{"avatar":"","nickname":"","mapname":"365","score":""}

Well and so, at request, the file that is created. But for some reason it responds with fail, not done. The request seems to be successful. What could be wrong?
Mistake:

Answer 1

What form should the response take? Maybe you need to apply dataType to text, for example?