Comments about O'Reilly Media High Performance JavaScript:

Nicholas Zakas has been putting up excellent content on his Blog for years, but this book is more than simply a rehash of that content. If you've never read Nicholas' writing, this is an amazing resource, but even if you have, there is content here that you may not have seen before.

But what's best, is that Nicholas reaches out to his friends and colleagues for topics that they are able to dive deeper into. Steven Levithan's chapter on Regular Expressions is probably the most informative thing I've read this year.

Comments about O'Reilly Media High Performance JavaScript:

This book is somewhat like a continuation of the Faster Web Sites and Even Faster Web Sites books which cover web sites performance more generally.

High Performance JavaScript goes much deeper into the scripting language but does also cover JavaScript's interaction with HTML and extensively covers JavaScript's interaction with the DOM.

One of the best things about the book is the extensive coverage of the subject. The topics are broken down into Page Load Times, Object usage, Dynamic DOM, Looping and Decision Statements, RegEx, User Controls/Interfaces, AJAX, Best Practice, etc. In each section the author provides graphs to show the relative time required by various techniques. For the most part, the best practices can be applied to any language.

Their are extensive examples provided for each technique. Also, there is coverage of libraries that can be used to provide functionality without reinventing the wheel and coverage of tools that can allow the developer to measure/benchmark their own code.

The one drawback might be that lots of techniques are demonstrated that pull data from sources then dynamically update the page. Examples might be real-time DOM scripting, using the innerHTML attribute, or modifying CSS on the fly. In these cases, the injected content needs to be sanitized or escaped for safety but I did not see examples of escaped content which could lead to mallicious injected content. However, the theme of the book is not security and the authors did mention this could be possible although "make safe" example are not given so I cannot reduce the rating on the basis.

The book covers its subject very well. Recommended for web developers and those who are learning JavaScript.