How to scope GA *and* GWO cookies to a single domain

Question

I use both Google Analytics and Google Website Optimizer on www.britely.com, and want to limit their cookies to that domain only. (To avoid cookie overhead in requests for static assets loaded from other subdomains of britely.com that should get some CDN love.)

An example page that uses both (and that currently sets the __utma, __utmb, __utmc and __utmz cookies on .britely.com, instead of on the wanted www.britely.com), is http://www.britely.com/ninjamom/s-t-dogs-think

As far as Google's docs go, it seems that a _gaq.push(['_setDomainName', 'none']); call (or ditto 'www.britely.com' instead of 'none') at the top of the page should be enough to achieve this goal.

Somehow, it isn't. I think we used to have even more cookies set on .britely.com before I read through the source of GWO's siteopt.js, which doesn't seem to know _setDomainName. It's responsive to a page-global constant _udn declaring the cookie domain it should use though - so leading in the page with this, at least GWO's __utmx and __utmxx cookies are handled correctly:

<script>
  var _gaq = _gaq || [], _udn = 'www.britely.com';
  _gaq.push(['_setDomainName', 'none']);
</script>

I know the common way of fixing the cookie overhead issue is to serve static content from some domain entirely different from the one using GA and GWO. That is not the solution I seek.

Answer 1

Besides the above tweaks, the Google Website Optimizer control script also needs its own _gaq.push(['gwo._setDomainName', 'none']); call - similar to the GA one, which only seems to be system global, but isn't.

With the above setup, all cookies get scoped to www.britely.com except for the __utmx and __utmxx ones, which end up scoped to .www.britely.com for some reason. Good enough for me.