NPAPI/ActiveX limitations?

The web browser plugin worlds is very new to me. So im hoping for someone to enlighten me on the possibilities and limitations of NPAPI/ActiveX plugins.

In particular can i run a sound thread thourgh an a browser plugin, even ASIO?

Also, can the JUCE gui be used through the browser then (just as in a standard app)?

Can they do anything (or are there some security concerns)?

You can do anything that you could do in a normal DLL, and yes, the juce gui can be used in the browser, of course.

…but! Some browsers are starting to use sandboxing to stop our fun! IE7 and 8 has a ‘protected mode’ that stops you doing anything that might be insecure, and gives the plugin its own fake file system to work in. (You can still do audio though)

Thanks for the lightning fast answer!

That’s great - so in theory i could compile the juce demo to run in the browser? Are there any juce-browser-plugin examples around?