I'm not certain. I think Dave Sim may have toyed with it for a couple of pages in early Cerebus (a "Mind Game" sequence), but could be wrong. It certainly has potential for development. There are other experiments tried at www.scottmccloud.com (his "Porphyria's Lover" is quite beautiful), and I'm sure there are more. There is no definitive approach to developing webcomics, and you're limited by your imagination. As someone pointed out on another forum, PDF (Acrobat) files are popular, probably because they provide diverse layout (instead of HTML's limited tables) and security (i.e. nobody can rip off your art and distribute it online unless they manage to crack your password).