Re: Mozilla could already do a lot for privacy
If they prohibit cross-domain JavaScript the whole jquery angular Web 2.0 bollocks would disappear up its own fundament overnight given that web designers are seemingly incapable of copying files across to their own domain and instead find it preferable to include them from elsewhere meaning they are at the mercy of third-parties deleting a left pad function or something.
And advertising and tracking would get killed overnight.
On second thoughts perhaps they should do it.