Ajax Web服务调用

I have the below code in my ASPX page to get some data from a webservice. I cannot use WCF so I am using the ASMX and .Net 3.5. However, what I get back is the yellow ASP.net error page talking about setting the web.config error tag to OFF. If I call my method from code behind and response.write it to the page I get a Json string that I have viewed in JSON Viewer and it parses fine. My issue here is the URL format. What am I doing wrong here. Every example I have found uses the webservice.asmx/Method format. I have also added the protocols to my web.config

<protocols>
    <add name="HttpGet"/>
    <add name="HttpPost"/>
</protocols>

Page Script:

 $.ajax({
        type: 'GET',
        contentType: "application/json; charset=utf-8",
        url: 'http://myserver/mywebservice.asmx/MyMethod',
        dataType: 'jsondata',
        success: function (msg) {
            var table = "<table><tr><th>ID</th><th>Title</th></tr>"
            for (var i = 0; i <= msg.length - 1; i++) {
                var row = "<tr>";
                row += "<td>" + msg[i].ID + "</td>";
                row += "<td>" + msg[i].Title + "</td>";
                row += "</tr>";
                table += row;
            }
            table += "</table>";
            $("#myDiv").html(table);
        },
        complete: function () {
            alert("complete");
        }
    });

Webservice:

    <WebMethod(), ScriptMethod(ResponseFormat:=ResponseFormat.Json, UseHttpGet:=True)> _
Public Function MyMethod() As String
    'removed for shorter post
End Function

UPDATE: So using the dev tools in Chrome I have found that part of my problem was the server was returning a 403 Forbidden error. After som tweaking I have come up with a partial solution that gives me back my data with json formatting. However, that json formatted text is now wrapped in XML. :-(

I have yet been able to figure out how to get the XML out of my json. Any ideas?

You should have

contentType: "application/json; charset=utf-8",
url: 'http://myserver/mywebservice.asmx/MyMethod',
dataType: 'jsondata',

similar to:

contentType: "application/json",
url: '/folderonmyserver/mywebservice.asmx/MyMethod',
dataType: 'json',
data: "{}", // needed for .Net not to blow up sometimes - or send real data

and in your success: reference msg.d (or have a translation to isolate that for .Net) given your .net version

success: function (msg) {
    var mydata = msg.d;
    var table = "<table><tr><th>ID</th><th>Title</th></tr>"
    for (var i = 0; i <= mydata.length - 1; i++) {