Specifically I would like to find out whether using mozilla it is possible to modify http header fields of form submissions (i.e. non-httprequest methods) Assuming a web server has been configured NOT to perform client authorisation, but the user / password information is still required by a CGI application a) it is possible using javascript to set user and password of the requester prior to issuing a form submit b) is this information passed in header field called AUTHORIZATION in HTTP1.1 and 1.0
