Sometimes, yes. If you've got real experience and the foundations are genuinely solid, there's no reason to sit through them again — skipping into a build-on program is a conversation worth having. But "experienced" is a word that hides a lot. Most people who want to skip the foundations have taught themselves in patches, and the patches don't line up. The stuff that looks basic from the outside (how the browser actually renders a page, how CSS inheritance really works, how to think about structure before you write markup) is usually where the gaps are — and gaps there will sink you in anything more advanced. The best way to find out is to tell us what you've built, what you're comfortable with, and what you're trying to do next. If you can skip, we'll say so. If the foundation has holes, we'll point at them — and you can decide whether to fill them here or somewhere else.