How do toolbars like the Meebo Bar work?

Question

Meebo's new 'bar' service puts a floating bar with links and chat functions at the bottom of any given webpage with just a dash of Javascript and HTML. I'd like to build something like it, but I'm flummoxed as to how they got around the same origin issues.

It looks like they're injecting an iframe and some script tags, but how they accomplish the rest of the functionality without a proxy is beyond me. Any ideas?

You can check out Meebo's service http://bar.meebo.com/ there and Robert Scoble seems to have it setup over on http://scobleizer.com.

NB: I don't mean to be a shill for either Meebo or Scoble, I'm just curious about the implementation.

Answer 1

HTTP GETs can be across domains, so part of the magic is in what method you utilize. There are also other methods for sending data to a different host than the one serving the page, like the window.name trick where information (usually less than 2k at a time) can be set to the window.name property (here is a link)

You can also utilize a little Flash player (flXHR works great)

Smart JavaScript can actually utilize which ever one is available. Also don't feel bad for shilling for Meebo those guys rock!