Submitted by Lukas_M on
User "iceiceice" took the CEGUI library and the Samples using OpenGL3 Core Profile Renderer and ported them to OpenGL ES2. This way he could use them with emscripten, making it possible to run CEGUI in your browser.
More Info here: http://cegui.org.uk/forum/viewtopic.php?f=4&t=7065
This is the link to the result: http://cbeck88.github.io/cegui-emscripten Try it out, it works really well!