问无法使用ajax调用调用WCF

EN

namespace InfraERP.WebServices
{
// NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "ICategoryMasterWCF" in both code and config file together.
[ServiceContract]
public interface ICategoryMasterWCF
{
    [OperationContract]
    [WebInvoke(ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped, RequestFormat= WebMessageFormat.Json)]
    string DoWork();

    [OperationContract]
    [WebGet]
    [WebInvoke(ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped, RequestFormat = WebMessageFormat.Json)]
    string sting(int id);

}


}

namespace InfraERP.WebServices
{
// NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "CategoryMasterWCF" in code, svc and config file together.
 [AspNetCompatibilityRequirements(RequirementsMode
= AspNetCompatibilityRequirementsMode.Allowed)]
public class CategoryMasterWCF : ICategoryMasterWCF
{

   public string DoWork()
    {
        return "Hello, It Worked! ";
    }

    public string sting(int id)
    {
        string _sting = "Number is " +id.ToString();
        return _sting;
    }

}
}

 $.ajax({
        type: "POST",
        url: '../WebServices/CategoryMasterWCF.svc/sting',
        contentType: "application/json; charset=UTF-8; charset-uf8",
        data: {id:"1"},
        processData: true,
        dataType: "json",
        success: function (msg) {
            alert(msg);
        },
        error: function (XMLHttpRequest, textStatus, errorThrown) {
            alert(textStatus + "---" + errorThrown);
        }
    });