If this is a CORS request, you may see all headers in debug tools (such as Chrome->Inspect Element->Network), but the xHR object will only retrieve the header (via xhr.getResponseHeader('Header')
) if such a header is a simple response header:
Content-Type
Last-modified
Content-Language
Cache-Control
Expires
Pragma
If it is not in this set, it must be present in the Access-Control-Expose-Headers header returned by the server.
About the case in question, if it is a CORS request, one will only be able to retrieve the Location
header through the XMLHttpRequest
object if, and only if, the header below is also present:
Access-Control-Expose-Headers: Location
If its not a CORS request, XMLHttpRequest
will have no problem retrieving it.