If only using JavaScript required a license to operate and came with a set of rules enforced by fines and jail time :)
If every browser had done the sane thing from day 1 (no third-party scripts and no cross-domain communication) we wouldn't be in the mess we're in. Sites could still use all the power that comes with scripting, ad networks just wouldn't be feasible.
That's fine. Now the first-party and ad peddlers have to work with and trust each other instead of using my machine, my ignorance and my disinterest in their dealings as an intermediary.
If every browser had done the sane thing from day 1 (no third-party scripts and no cross-domain communication) we wouldn't be in the mess we're in. Sites could still use all the power that comes with scripting, ad networks just wouldn't be feasible.