var Client = {
  Engine: {'name': 'unknown', 'version': ''},
  Features: {}
};

Client.Features.xhr = !!(window.XMLHttpRequest);
Client.Features.xpath = !!(document.evaluate);

if (window.opera) Client.Engine.name = 'opera';
else if (window.ActiveXObject) Client.Engine = {'name': 'ie', 'version': (Client.Features.xhr) ? 7 : 6};
else if (!navigator.taintEnabled) Client.Engine = {'name': 'webkit', 'version': (Client.Features.xpath) ? 420 : 419};
else if (document.getBoxObjectFor != null) Client.Engine.name = 'gecko';
Client.Engine[Client.Engine.name] = Client.Engine[Client.Engine.name + Client.Engine.version] = true;