I originally gave this book 1 star because of the outrageous number of errors. I spent an hour going through the website's Errata trying to make all the corrections. However, even many of the corrections are murky, directing you to download updated code examples that don't exist. The author seems to have left this book for dead, even providing a dead email address on the website. The last straw was when my copy started falling apart...

Update: I was so disappointed with the quality of this book that I called the publisher (Wiley) to complain. They confirmed my issues and said that they were issuing free replacements of the book. In my case, having purchased from Amazon, they said I would have to go through the Seller, which I did. The seller ended up issuing me a full refund.

I re-purchased the latest printing of the book at Barnes & Noble and can report that all the errors have been corrected and the binding issue seems to have been resolved. So...

My warning to you is to avoid purchasing this book from Amazon, because you will not be able know if you have an older version with the above issues or a newer version without the issues.

That being said, I now give this book 4 stars. It is very thorough in explaining JavaScript in detail. My only two complaints are:

(1) the lack of any exercises to re-enforce the material; you read something then move on to the next subject. A lot of the material didn't "stick" without a way to re-enforce the concepts.

(2) I felt the book lacked real-world insights about JavaScript. For example, the newer .querySelector() is far superior and more flexible than .getElementById() or .getElementsByClassName(), but all were described matter-of-factly, without any descrimination. It was left up to you to figure out when or why, all things being equal, to use one over the other.

Finally, if you already have a good grasp of JavaScript, this book is a very good reference.