How does Wowhead.com do item popups across fansites?

If you run a site that links to world of warcraft items, you're probably using the wowhead.com javascript to bring their item popups to your site. See it in action here, mouse over the "King Dred's Helm" link. It will popup Wowhead.com's info.

is this just a jsonp callback to their site?

I want to i开发者_开发问答mplement something like this on my site. Perhaps it could be done using jQuery html fragment and a jsonp callback to my own site?

yes it's JSON or ajax call

If you want this exact functionality check out this article on how to add wowhead tooltips on your site.

But, if you are after a generic tooltip, I'd definitely recommend qTip, which can handle dynamic tooltip content.