I've been teaching programming for five or six years now. I always start with HTML, then add CSS, and then add JavaScript. That way they experience mastery all the way, and see how they can be creative with the code. It's so great to see a pupil "get it" -- and sometimes even pupils that "suck at math" or even pupils who have problems spelling the most basic sentence correctly. In fact I've found that there's a strange correlation where pupils who have dyslexia often seem to be better than others at programming.