Back in the late 1990s, when I was at grad school VRML was going to take over the world. My peers and I built all manner of useful and interesting things with it by hooking it u
A-Frame is an open-source Web3D/WebVR framework in the same veins. It is a Javascript library rather than trying to be a standard. Like X3DOM, it allows you to author 3D scenes with HTML, although its entity-component-system pattern makes it much more extensible. While it has a focus on VR, it also functions as a general-purpose (three.js) 3D framework.