Your best bet is to either immediately delete the script tags after the dom tree is loaded, or dynamically create the script tag in your javascript.

Either way, if someone wants to use the Web developer tool or Firebug they will still see the javascript. If it is in the browser it will be seen.

One advantage of dynamically creating the script tag you will not load the javascript if javascript is turned off.

If I turned off the javascript I could still see all in the html, as you won't have been able to delete the script tags.

Update: If you put in <script src='...' /> then you won't see the javascript but you do see the javascript file url, so it is just a matter of pasting that into the address bar and you d/l the javascript. If you dynamically delete the script tags it will still be in the View Source source, but not in firebug's html source, and if you dynamically create the tag then firebug can see it but not in View Source.

Unfortunately, as I mentioned Firebug can always see the javascript, so it isn't hidden from there.

The only one I haven't tried, so I don't know what would happen is if you d/l the javascript as an ajax call and then 'exec' is used on that, to run it. I don't know if that would show up anywhere.