I did comment on Ralf's web site, but I thought it would be useful to know:
The plugin doesn't work in Safari. The reason it doesn't work in Safari is because the script element doesn't fire any events when the external library is loaded, and hence listening for the onreadystatechange doesn't work. I wrote an entry on how to get around this problem, but I'm not sure it will be helpful to your plugin without replicating the core test: http://remysharp.com/2007/04/12/how-to-detect-when-an-external-library-has-loaded/
