According to section 14.14 of rfc2616, the base URI of a document is given by the Content-Location: header, if present.

By following this link, you will see if your browser is following or violating the spec. In the latter case, you are encouraged to report this bug to the relevant support service of your browser vendor.

Here is the list of User-Agent following RFC2616 on this tests:

• Amaya 7.0 and above (all OSes)
• Opera 7.0 8.* but NOT 9.0 (all OSes)