WebRequest.jsm
usage to import webrequest, use code like: let {webrequest} = cu.import("resource://gre/modules/webrequest.jsm", {}); the webrequest object has the following properties, each of which corresponds to a specific stage in executing a web request: onbeforerequest onbeforesendheaders onsendheaders onheadersreceived onresponsestarted oncompleted each of these objects defines two functions: addlistener(callback, filter, opt_extrainfospec) removelistener(callback) adding listeners use addlistener to add a listener to a particular event.
... modify response headers onheadersreceived responseheaders array of http headers.
... onheadersreceived triggered once response headers have been received.
... redirection is not allowed in onbeforerequest or onheadersreceived, but is allowed in onbeforesendheaders.