This page requests a resource on another domain that typically sets a simple counter Cookie, and thus the resource is requested with Cookies using the withCredentials API flag on XMLHttpRequest (implemented in Firefox 3.1). The contents returned by the other domain vary depending on the value of the simple counter Cookie that accompanies the request.

This XHTML document GETs another resource using cross-site XHR and sends that request with credentials. If you get a response back, the content of that response should reflect Cookies being sent, since the XMLHttpRequest invocation on this page sets the withCredentials flag.