jQuery + Webservices: Webservice not returning JSON, only XML

Looks like it just doesnt want to work...

@ Webservice:

<ScriptMethod(UseHttpGet:=False, ResponseFormat:=ResponseFormat.Json), WebMet开发者_开发问答hod()> _
    Public Function LoginDB(ByVal user As String, ByVal pass As String) As String
        global.user = user
        global.pass = pass
        If (<<lots of code to check if user is valid>>) Then
            Return "1"
        Else
            Return "0"
        End If
    End Function

The webservice DOES work, if the user is valid, returns 1 otherwise 0. But I always get it as XML

<?xml version="1.0" encoding="utf-8"?>
<string xmlns="http://tempuri.org/">"0"</string>

@Jquery:

$.ajax({
                type: "POST",
                contentType: "application/json; charset=utf-8",
                url: "Services/Autenticacao.asmx/LoginDB",
                data: "{'user':'ale','pass':'123'}",
                dataType: "json",
                success: function(data) {
                    alert(data);
                },
.....

Anyone?

You need to post your jQuery, but are you using the getJson jQuery method? If not you need to explicitly set the correct data type:

$.ajax({
  type: "POST",
  contentType: "application/json; charset=utf-8",
  url: "WebService.asmx/WebMethodName",
  data: "{}",
  dataType: "json"
});

Or use the getJSON method:

$.getJSON('WebService.asmx/WebMethodName', function(data) {
    //Do something with JSON response (data)
});

If you want your webservice to return JSON

asked and answered... How to return JSON from a 2.0 asmx web service