My application has two windows, which both load content from a protocol
handler. Only one of them has python permissions for this example.
I tried making the protocol handler serve up HTML with the following script
tag in the head:
    <script type="application/x-python"> 
from mozutils import doAlert, doQuit
doAlert("Security Violated!!! Aborting.")
doQuit(True)
</script> 

This does quit, but gives logs the following to the console twice:
WARNING:xpcom:Python DOM script error
<type 'exceptions.SystemError'> : NULL object passed to Py_BuildValue

Changing it to doQuit(False) gives an exception, and will close one of my
two windows - the one without python permission (and if I then reload
content in the one which is still there, I can get it to crash):
Traceback (most recent call last):
  File "/afs/
cc.monash.edu.au/users/b/p/bpmor3/bpbibleng/xulrunner/pylib/nsdom/context.py",
line 432, in EvaluateString
    exec co in glob
  File "bpbible://esv/Matthew%202:1", line 15, in <module> 
  File "/afs/cc.monash.edu.au/users/b/p/bpmor3/bpbibleng/pylib/mozutils.py",
line 16, in doQuit
    appStartup.quit(quitSeverity)
  File "<XPCOMObject method 'quit'> ", line 3, in quit
<class 'xpcom.Exception'> : -2147467259 (-2147467259)

doQuit is taken from one of the python xpcom samples:
def doQuit(forceQuit=False):
    appStartup = Components.classes['@
mozilla.org/toolkit/app-startup;1'].getService(Components.interfaces.nsIAppStartup)<http://m
ozilla.org/toolkit/app-startup;1%27%5D.getService%28Components.interfaces.nsIAppStartup%29> 

    # eAttemptQuit will try to close each XUL window, but the XUL window can
cancel the quit
    # process if there is unsaved data. eForceQuit will quit no matter what.
    if forceQuit:
        quitSeverity = Components.interfaces.nsIAppStartup.eForceQuit
     else:
        quitSeverity = Components.interfaces.nsIAppStartup.eAttemptQuit
    appStartup.quit(quitSeverity)

God Bless,
Ben
-------------------------------------------------------------------------------------------
Multitudes, multitudes,
   in the valley of decision!
For the day of the LORD is near
   in the valley of decision.

Giôên 3:14 (ESV)