AJAX, Tooltip, World of Warcraft (WoW)

Spend a whole day trying to work around a simple issue.
I give myself one html page.  No server side code.
Write a javascript/css based approach to pull data from either Thottbot or Allakhazam and return the data, then render it as a popup.

The AJAX isn't hard, nor is the pop-up page, the problem lies in the "no server side code".

Both IE and FireFox don't like to make XMLHttpRequest cross-domain.  That is, it doesn't like being hosted on a http://localhost/test.html or even file host file:///test.html, making a request to thottbot.com.
On IE, you get a security question pop'up everytime you try to make such a call.  If the user clicks "OK", he'd be let through.
On FireFox, it's automatically denied unless you try to obtain UniversalBrowserRead privilege.  Extremely difficult and potentially a security loophole.

The solution seems bleak.

Use AJAX to query the origin server - without making a cross-domain call.  But use the server to make the 'translation' - possibly caching as well.