The goal is to ‘soften’ hyperlinks off to external content slightly by displaying an external link bar at the top of the window, that displays above the content on the external website – containing a line of text that reads something along the lines of “The content you are viewing is not owned by this site, close this browser window to return to site name“.
I know there’s a way to achieve this using frames, but as far as I understand it frames are bad news for accessibility. Furthermore, if the user then accesses a site which itself has a frame set, there can be all sorts of fun and games!
Would welcome any feedback. Could something like this be achievable with jQuery perhaps?
No, you need to use frames. You need to have some degree of control, and the only way you can do that with remote addresses, is by keeping the user on your server, and showing the remote pages in a frame.
That being said, if the remote sites have a partnership with you, you could discuss a javascript option which displays a bar on the top of their pages whenever a specific cookie is set indicating the traffic came from your site initially.