Calling a code behind function from JQuery

function TestFunction(ddlType){
    
    $.ajax({
        type: "POST",
        contentType: "application/json; charset=utf-8",
        url: "../Script Services/AutoComplete.asmx/SampleWebMethod",
        datatype: "JSON",
        parameters: { param1: ddlType },
        data: "{intTypeID: " + intTypeID + "}",
        success: function (response) {
            TestFunctionOnSuccess(ddlType, response.d);
        }
    });}

[WebMethod(EnableSession = true)]
[System.Web.Script.Services.ScriptMethod]
        public SampleObject[] SampleWebMethod(int? intTypeID)
        {
            DataTable dt = new DataTable();
            dt = ProjectBusinessLayer.Type.TypeSelect(intTypeID.Value);

            List<SampleObject> Details = new List<SampleObject>();
            foreach (DataRow dtrow in dt.Rows)
            {
                string TestID = dtrow["TestID"].ToString();
                string TestValue = dtrow["TestValue"].ToString();
                Details.Add(new SampleObject(TestID, TestValue));
            }
            return Details.ToArray();
        }

function TestFunctionOnSuccess(ddlType, lstTestDetails) {

// Do the functionality you need

}