$.ajax({
        type: "POST",url: "*TCSection.ascx/InsertTCSection",data: "{id:'" + id + "'}",contentType: "application/json; charset=utf-8",dataType: "json",success: function (msg) {
            var URL = msg.d;
            alert(URL);
        });

.cs代码

[WebMethod]
public static string InsertTCSection(string id)
{
    string result = "deneme";
    return result; 
}