I think comparing script steps to the HTML/CSS code of FileMaker WebDirect pages is like comparing apples to eggs (not even oranges!). Just because you can do one thing doesn't necessarily translate to logically being able to or even needing to do the other.
I think you need to understand what it is that FileMaker WebDirect gives you - everything, rendered on a web page. You don't want to go messing with the underlying code. And what FileMaker WebDirect does is so much more than the code you can see on a page.