Question

How can I open a tab with a custom referrer in a Firefox add-on?

I guess something like that:

tab.addProperty("referer", "http://mywebsite.com/");

Answer 1

You cannot “add” a referrer to an already open tab, the referrer needs to be specified when the tab is opened. You use gBrowser.addTab() method for that:

gBrowser.addTab("http://example.com/", {referrerURI: "http://referrer.com/"});

gBrowser is a global variable in the browser window. If you don’t have the browser window, you can use nsIWindowMediator.getMostRecentWindow() for that:

var windowMediator = Components.classes["@mozilla.org/appshell/window-mediator;1"]
                               .getService(Components.interfaces.nsIWindowMediator);
var window = windowMediator.getMostRecentWindow("navigator:browser");
window.gBrowser.addTab(...);