$ .Ajax接受所有字符集

Question

i call this $.ajax method :

$.ajax({
    type: 'POST',
    data: JSON.stringify(data),
    contentType: 'application/json',
    url: 'http://46.101.209.16/endpoint',
    success : function(etichettas) {
        console.log(etichettas);

        var blob = new Blob([etichettas], {type: "application/pdf"});
        saveAs(blob, "Label.pdf");
    }//SUCCESS
});

and the "etichettas" is a pdf. the problem is that some chars : ���� how can i set the ajax call to see the original chars and don't chane it in � ? sorry for bad english, i'm tialian (: