Autopackage JavaScript

From the autopackage site:

Another way is to use some simple JavaScript to detect which distribution the user is running, and only present the downloads that are relevant for them. We hope to shortly launch a new service to the open source community that makes this easy: you will be able to add a script tag pointing to a file on our site, and along with some simple annotated HTML have an automatically generated, context-sensitive downloads page.

Note: we also want this for Jokosher, eventually.