I've used
libGDX before and can recommend it. It's a Java framework but it can be run in your browser.
Urho3D might be a possible option. It's written in C++, but it supports cross compilation to asm.js (using emscripten) and thus can be run in your browser. They have samples you can look at here:
https://urho3d.github.io/samples/
Unity3D might be another option, although it requires users to install a browser extension ("Unity Web Player") which may be undesirable.
Other than that, have you tried looking for some Javascript 3D libraries, such as
three.js?