False dichotomy. OP could have tested for FF if he wanted to, irrespective of the framework he has chosen. Personally, I develop Firefox-first and then work on

False dichotomy. OP could have tested for FF if he wanted to, irrespective of the framework he has chosen. Personally, I develop Firefox-first and then work on compatibility for lesser browsers like Chrome and Safari. Of course things have been complicated a bit now that Firefox Focus is out and uses Webkit...