You just have to get used to it. Don't even try to begin comparing JS and XHTML/CSS. JS is a programming language (to put it simply, even though it's not exactly), while XHTML/CSS is markup. You just have to get into the mindset and learn the syntax.

For me, JS isn't hard, it's just getting used to the DOM and debugging. JS has a horrible reputation, for me, for being very difficult to debug since a lot of the errors by plugins and programs such as Firebug are sometimes really vague and don't give you ful information.