I just mentioned the sale O'Reilly is having on HTML5 Books, and it turns out they are also having a sale on JavaScript Books.
Some really, really good books on JavaScript. I own and have read most of them and consult a lot of them on a daily basis for the various JavaScript Patterns and Practices.
I have written a few book reviews on some of them, but many of them I have not.
I would do some googling as to ones people recommend. I personally read a lot and have enjoyed most of them.
Check out the O'Reilly sale on JavaScript books.
O'Reilly is having a sale today on HTML5 Books and Videos.
I have read a few of the HTML5 Books and, if you are interested, you can read the book reviews:
In general, if you are new to JavaScript and HTML5, I would jump on the Head First HTML5 Programming Book at 50% off. Although sometimes the explosion of media in the book can be a bit much, the information on JavaScript and problem-solution approach to using the new programming features of HTML5 are awesome! HTML5 The Missing Manual is great for those new to HTML5 and looking for information not only on the programming features of HTML5, but a lot on the new tags and semantic markup. The online resources mentioned in HTML5 The Missing Manual are worth the price of the book alone.
If you are interested in HTML5 but have been waiting on a deal, O'Reilly's 40% - 50% off deal on HTML5 Books and Videos is a good deal.
Btw, O'Reilly is having a sale on JavaScript books as well!