If you can use LiveConnect (a big if), you can get at the DOM of the web page, and get the parameter names through the applet tag.
I think getParameterInfo was meant for the browser to call, so that it could show the creator of the web page what parameters to put into it. The HotJava browser used to do something along those lines. (There are similar methods for
servlets, also universally ignored, only honored by Suns JavaWebServer.)