I'm the creator of http://plnkr.co/edit/ which is a similar (but perhaps less 'professional') online web editor.
One thing that I find interesting is that Mozilla has decided that browsers have moved forward far enough that hosting the preview via `blob:` urls. I've experimented with a similar approach but had issues where different 3rd party libraries die unexpectedly when they are not dealing with http / https.
One thing that I find interesting is that Mozilla has decided that browsers have moved forward far enough that hosting the preview via `blob:` urls. I've experimented with a similar approach but had issues where different 3rd party libraries die unexpectedly when they are not dealing with http / https.