showing errors in ajax

In master page  

 <% if (HttpContext.Current.IsDebuggingEnabled) { %>

    <meta name="debug" content="true" />

    <% } %>

In javascript

        //EVENT Error

        error: function (result) {

            HideProgress();

            if ($("meta[name=debug]").attr("content") == "true") {

                //Full Error when debugging

                var errDoc = window.open();

                errDoc.document.write(result.responseText);

                errDoc.document.close();

            } else {

                // generic error message for production use

                Message("An unexpected error occurred.", "Error");

            }

        }