// Provide a default path to dwr.engine
if (dwr == null) var dwr = {};
if (dwr.engine == null) dwr.engine = {};
if (DWREngine == null) var DWREngine = dwr.engine;

if (Ping == null) var Ping = {};
Ping._path = '/dwr';
Ping.getEmptyString = function(callback) {
  dwr.engine._execute(Ping._path, 'Ping', 'getEmptyString', callback);
}