function onComplete(id, xhrOrXdr, isError) {
        var response = null;

        /* jshint eqnull:true */
        if (xhrOrXdr.responseText != null) {
            try {
                response = qq.parseJson(xhrOrXdr.responseText);
            }
            catch (err) {
                options.log("Problem parsing session response: " + err.message, "error");
                isError = true;
            }
        }

        options.onComplete(response, !isError, xhrOrXdr);
    }
Thin module used to send GET requests to the server, expecting information about session
data used to initialize an uploader instance.

@param spec Various options used to influence the associated request.
@constructor