webOS skill level: Beginner
You already understand the basics of HTML, so start with this tutorial:
If you're looking for more, go to this page and step through lessons in the the HTML Advanced section:
If you're finding things are going over your head, check out the beginner tutorial.
For intermediate CSS, check out this tutorial:
For more advanced lessons, go through the CSS Advanced lessons at w3schools, starting with this one:
Even developers who have been using CSS for a while will probably learn something new by stepping through these lessons.
Go through the JS Objects and JS Advanced lessons.