The Unigine Sanctuary/Crypt tech demo has been ported to run natively in modern web-browsers -- without any plug-ins -- through the use of Emscripten
and now it's proven that the Unigine Engine with its intense OpenGL visuals can even be brought into the web-browser.
Read this Mozilla.org blog post
about bringing Unigine to the web. You can try out the impressive web-based demo at Unigine.com