Thread:Project:Support desk/logins and watchlist via API

I am a beginner at the API. I noticed if I run a command from the browser: it shows me my watchlist because I am currently logged in. But if I run a similar query from javascript, on a local html page, it says I am not logged in. I assume the first works because of cookies?
 * http://en.wikipedia.org/w/api.php?action=query&list=watchlist

The bigger picture: I was thinking of making a page which shows a user's watchlist in a novel way, just as an experiment. I was hopping I could just put a link on wikipedia, and people could visit the page and see their watchlist. But now I'm guessing I might have to do a whole login sequence? Also can a user script resolve this? I was trying to start with an external site just because I figured it would be less to learn.