As seen in the above screenshot, Spectral Workbench (finally) also works on Firefox and Firefox for Android.
Try it out: https://spectralworkbench.org/capture
What's nice is that for Android users, Firefox has implemented camera selection, which the Google Chrome team has not -- so you won't get stuck using a front-facing camera.
Addendum: Firefox OS does not seem to have fully implemented the HTML5 WebRTC webcam API but I am told it will appear very soon. Not that all that many folks have firefox os, but it'd be nice.