Just finished my first draft of Periscope, the tentative name for my tiny Greasemonkey project. The idea is that you don't always know what the semantic content on the other side of a URL is without having to visit it, and there's not a consistent way to get previews from them. Periscope takes care of this problem by providing semantically relevant tooltips for each supported domain. For example, if a YouTube link is present on a page, that link's tooltip will be appended with the title of the YouTube video on the other side. (Handy for avoiding rickrolls!)

Right now I support is.gd, tinyurl.com, and YouTube. It's absurdly simple to hack on and extend to support your own sites in whatever way you choose -- more details on that in a future post.

So far it works pretty well -- I'm impressed that not much effort went into this and I still got a high-quality result. Huzzah! Unfortunately, I don't really have a good solution for unit-testing these at the moment, so if you have suggestions for doing that with Javascript sources, please do drop me a line.

You can get the source and install it over at Userscripts. As this is a Greasemonkey script, you will of course need the Greasemonkey Firefox extension if you don't already have it.