Three.js runs in all browsers supported by WebGL.
Actually all browsers are supported which have support for canvas. We do not support polyfilled canvas. Mainly because most of the time, we use other things beside the canvas that are not implemented by the browser.
A quick look at http://caniuse.com/webgl reveals browsers that lack WebGL support are:
- IE < v11 (v11 is latest version)
- Android Browser < v51 (v51 is latest version)
- iOS Safari < v8
- Opera Mini (all versions)