I\'m using PHP to send html emails. I\'ve tried to import css files inside the email, and it works fine.
@Karim79, I'm not convinced that the answer is so clear cut as you suggest.
It all depends on the environment used to read the email, and whether that environemnt supports javascript or not. Admittedly, I suspect that most email readers would be averse to supporting javascript, in order to avoid viruses and malware, but there is no absolute reason why this couldn't be done.
Having said that, the unpredictable level of support offered by readers would probably mean that you shouldn't rely on the script running correctly (if at all), so you'd probably want to take a 'graceful degradation' approach.