This is a sample 3 layer horizontal navigation bar done purely in CSS, no JavaScript at all!
In case you were wondering, the menus I shown here are based off the menus in Opera. I can't think of anything to display so I thought of just emulating some of my browser's menu bars.
I left out two sub-menus in the View menu though - Style and Encoding. They had too many child content and I didn't feel like adding them all, haha!
Some panels might be quite lacking in width, for those you'd want to use an inline width adjustment. If you'd view the source code of this page, you'd see me do the inline width adjustment at line number 64 for the "Toolbars" and line 95 for the "Images" sub-menu.
I also applied a basic skin just to show that this can be easily customized using your own CSS declarations.
Read about this entry in my blog - A neat and clean CSS menu