I bought this book because I have been building static websites with HTML/CSS for a while and wanted to see if I could take this skill to the next level. I think this book brought me a long way towards that aim. I would recommend it to anyone who knows AT LEAST basic HTML and preferably has some programming experience as well. You don't have to be a wiz, but it helps if you know the concepts of loops and objects in other languages.
When introducing a new language, the author tends to tell you A LOT about the syntax of the language before going into any detail about what you can do with it. The best way to read the book is to have a project in mind as you go through these chapters, and try to incorporate new concepts as they come up. Of course, this will probably make your project a mess by the time it's done, but in the end it's a learning exercise. The book is full of code snippets to demonstrate functionality, but a bit lacking in what I would call real-world examples (until the last chapter).
In conclusion, I may not buy another book on PHP and MySQL for a long time. This one is thorough enough that I can find my way around and find anything else I need with online reference guides. But I think, conceptually, the JS section falls down a bit. Still, after I pick up a more basic JS guide, I'll likely keep this one around because of level of detail it goes into.
The chapter on CSS3 was also a great way to get up to speed on the latest additions to that whole thing.