HOWTO: Bypass/evade the same origin policy security restriction

(A manifestation of this is Firefox's "Permission denied to call method XMLHttpRequest.open" security exception.)

I never did completely figure this out, but the solution theoretically involves putting

user_pref("signed.applets.codebase_principal_support", true);

in prefs.js, then calling 

netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead");

(pops up a confirmation dialog to the user) just before doing the call.

See:

HOWTO: Disable access keys (shortcuts)

To disable access keys, so you aren't surprised when you hit Ctrl-P, etc. set the ui.key.contentAccess preference (access via the URL about:config) to 0.

FAQ: Where are older versions of Firefox? (e.g. Firefox 2)

http://www.mozilla.com/en-US/firefox/all-older.html

FAQ: Where are older versions of Firebug? How to downgrade Firebug?

See, e.g.

http://getfirebug.com/releases/firebug/1.2/

FAQ: How to test XPath queries?

The console exports the function $x() which can be used to perform ad hoc XPath queries:

$x('/html')