I'd like to create a virtual space where I want to mix 3D elements and html content. I have seem some demos with WebVR but didn't work for me. WebAR is also an interesting option.
Thanks
Unfortunately, this isn't possible at the moment, because
There is certainly work being done in both directions, but your best bets would probably be a-frame (https://aframe.io/) or reactVR (https://developer.oculus.com/blog/introducing-the-react-vr-pre-release/) which both at least have a bit of that html-feeling to it and can handle text pretty well (nothing compared to the power of html+css, but they will get there at some point).
Another option is to use a library like html2canvas (https://html2canvas.hertzen.com/) to get some rendered output from a piece of html which you can then use as a texture. Also has it's limits but might be worth a try...
Have fun!