// *** Service Calling Proxy Class
function serviceProxy(serviceUrl) {
    var _I = this;
    this.serviceUrl = serviceUrl;

    // *** Call a wrapped object
    this.invoke = function(method, data, callback, error, bare) {
        // *** Convert input data into JSON - REQUIRES Json2.js
        var json = JSON2.stringify(data);

        // *** The service endpoint URL        
        var url = _I.serviceUrl + method;

        $.ajax({
            url: url,
            data: json,
            type: "POST",
            processData: false,
            contentType: "application/json",
            timeout: 10000,
            dataType: "text",  // not "json" we'll parse
            success:
                    function(res) {
                        if (!callback) return;

                        // *** Use json library so we can fix up MS AJAX dates
                        var result = JSON2.parse(res);

                        // *** Bare message IS result
                        if (bare)
                        { callback(result); return; }

                        // *** Wrapped message contains top level object node
                        // *** strip it off
                        for (var property in result) {
                            callback(result[property]);
                            break;
                        }
                    },
            error: function(xhr) {
                if (!error) return;
                if (xhr.responseText) {
                    var err = JSON2.parse(xhr.responseText);
                    if (err)
                        error(err);
                    else
                        error({ Message: "Unknown server error." })
                }
                return;
            }
        });
    }
}
// *** Create a static instance
var Proxy = new serviceProxy("/RenderAJAX/AJAXService.svc/");