Cross domain iFrame - cookie is not transferred - iframe

Question

we have a website with our application running in an iFrame on multiple domains and subdomains. The main website (www.example.com) has only static content with links to the sites with framed application sites. So sub.example.com, sub2.example.com, search.another.com have all iFrame with the application running.
We'd like to track all these sites with Google Analytics (GA). Subdomain tracking is working fine but I couldn't find a way to make the cross domain work accurately. The main issue is I cannot share the visitor cookie information among the top level domains. So, the same visitor who goes to sub.example.com and search.another.com get 2 different cookies, which result in various issues. (e.g. inflated visitor counter, cannot correctly track referral info, etc)
Can you please help me fix this?
(I've done a pretty thorough search on the web, tried several scenarios but no luck so far)
Here is the core of our GA implementation:
on sub.example.com (and all subdomains of the main website)
_gaq.push(['b._setAccount', 'UA-XXX']);
_gaq.push(['b._setDomainName', 'example.com']);
_gaq.push(['b._setAllowLinker', true]);
_gaq.push(['b._addIgnoredRef', 'example.com']);
_gaq.push(['b._addIgnoredRef', 'search.another.com']);
_gaq.push(['b._trackPageview']);
on search.another.com (all external subdomains have variants)
_gaq.push(['b._setAccount', 'UA-XXX']);
_gaq.push(['b._setDomainName', 'search.another.com']);
_gaq.push(['b._setAllowLinker', true]);
_gaq.push(['b._addIgnoredRef', 'example.com']);
_gaq.push(['b._addIgnoredRef', 'search.another.com']);
_gaq.push(['b._trackPageview']);
just after iframe on all pages
<script type="text/javascript">
_gaq.push(function ()
{
var iFrameTracker = _gat._getTrackerByName('b');
var iframe = document.getElementById('myframe');
iframe.src = iFrameTracker._getLinkerUrl(iframe.src);
});
</script>
on the link on www.example.com
<a href="http://search.another.com" onClick="_gaq.push(function ()
{
var tracker = _gat._getTrackerByName('b');
var linkerUrl = tracker._getLinkerUrl('http://search.another.com');
});">
linkerUrl has the correct Url with the cookie of www.example.com. But for some weird reason, GA assigns a new cookie on the search.another.com. I tried setting the domain name to none (['b._setDomainName', 'none']), which didn't help. I'm not sure if I'm missing a simple fundamental point here. I guess the issue might be related to having cross domain iFrames and the links can be either in the iFrame or in the frameset. So I want to track both.
I do the debugging with the Chrome GA Debugger addon.
(Btw, theoretically we can have infinite number of top-level / sub domains. So manually creating filters for each domain on GA is not an option. )

Answer 1

You're simply assigning the linkerUrl to a variable. You need to redirect the user to that url instead.
You should return false on the onClick handler to keep the browser from doing the usual redirect.
<a href="http://search.another.com" onClick="_gaq.push(function ()
{
var tracker = _gat._getTrackerByName('b');
var linkerUrl = tracker._getLinkerUrl('http://search.another.com');
window.location.href = linkerUrl;
});return false;">
Alternatively you should be using _link. Which does pretty much the same thing.
<a href="http://search.another.com"
onClick="_gaq.push(['b._link', this.href]);return false;">