Signing your JavaScript code lets it gain extra privledges, such as accessing the urls of windows from other sites. You can find out all about it at 
http://www.mozilla.org/projects/security/components/signed-scripts.html
<html> <head>
<title>!JavaScript test</title>
</head> <frameset rows="10%,*">
<frame src="snoop.html"> <frame src="
</frameset> </html>
<html> <head>
<title>snoop</title> <script type="text/javascript">
<!-- function init() {
window.setTimeout('snoop()', 100);
} function snoop() {
try {
netscape.security.!PrivilegeManager?.enablePrivilege('!UniversalBrowserRead?');
var url = top.frames[1?.location.toString(); document.getElementById('text').innerHTML = url; window.setTimeout('snoop()', 1000);
} catch (e) {
document.getElementById('text').innerHTML = 'Exception: ' + e;
}
} // -->
</script>
</head> <body onLoad="init();">
<tt id="text">loading...</tt>
</body> </html>
Then load frame.html in Mozilla1? with a local url (e.g. one starting with file://). You'll get a message asking if you want to grant the script enhanced privileges. Click No and you'll see an exception message in the upper frame. Reload, tick the remember box (or you'll get asked once a second) and click Yes. Now you'll see the url of the lower frame in the upper frame. It'll follow as you click around.
Now copy the two files to your webserver and try loading frame.html from there. It doesn't work as the script isn't signed. Go to http://ftp.mozilla.org/pub/security/nss/releases/ and download a copy of the latest version of NSS for your operating system and to http://ftp.mozilla.org/pub/nspr/releases/ to download a copy of the latest NSPR. Unpack them and do whatever it is you need to do put the files in the bin directory in your path and the files in the lib directory in your library path.
to
<frame src="jar:
Load up http://localhost/path-to-files/frame.html and all should be well.
That's all i know about signing JavaScript. The next step would be to get a real signing certificate so you could distribute your code. It doesn't seem to be possible to export the certificate you made with signtool, but if anyone figures it out, please edit this page!
Information about creating Root CA's and other certificates see SSLNotes
1? NetscapeNavigator 4 doesn't support the JavaScript try/catch statements, so it worn't work with the given code. If you take them out it should work. The netscape.security object doesn't exist for non-signed scripts, so you can use that to detect if you can access the permissions.
No other page links to SignedJavaScript yet.
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