DOM Events in 3D Space is a tutorial by Jerome Etienne that demonstrates how to use threex.domevent.js. The 3D DOM event demo shows how this works -- click on each teapot and different animations will be triggered.
THREE.Ray is used, in particular the
intersectScene method, to determine if an event intersects an object.
./bin/lowkick command ie6 test/config.json
This example, given suitable tools, will run tests in IE using VirtualBox. Headless testing is documented in the project's readme, but it'll need a little bit of effort to get it working.
Other drivers can be used, or added through configuration files. For example, LowKick comes with a Node driver, VirtualBox, and "virtualbox-ie".